Apparatus and method for maintaining and/or restoring viability of organs

ABSTRACT

An organ perfusion apparatus and method monitor, sustain and/or restore viability of organs and preserve organs for storage and/or transport. Other apparatus include an organ transporter, an organ cassette and an organ diagnostic device. The method includes perfusing the organ at hypothermic and/or normothermic temperatures, preferably after hypothermic organ flushing for organ transport and/or storage. The method can be practiced with prior or subsequent static or perfusion hypothermic exposure of the organ. Organ viability is restored by restoring high energy nucleotide (e.g., ATP) levels by perfusing the organ with a medical fluid, such as an oxygenated cross-linked hemoglobin-based bicarbonate medical fluid, at normothermic temperatures. In perfusion, organ perfusion pressure is preferably controlled in response to a sensor disposed in an end of tubing placed in the organ, by a pneumatically pressurized medical fluid reservoir, providing perfusion pressure fine tuning, overpressurization prevention and emergency flow cut-off. In the hypothermic mode, the organ is perfused with a medical fluid, preferably a simple crystalloid solution containing antioxidants, intermittently or in slow continuous flow. The medical fluid may be fed into the organ from an intermediary tank having a low pressure head to avoid organ overpressurization. Preventing overpressurization prevents or reduces damage to vascular endothelial lining and to organ tissue in general. Viability of the organ may be automatically monitored, preferably by monitoring characteristics of the medical fluid perfusate. The perfusion process can be automatically controlled using a control program.

This is a Continuation of application Ser. No. 12/662,930 filed May 12,2010, which is a Division of application Ser. No. 10/617,130 filed Jul.11, 2003, now U.S. Pat. No. 7,824,848, which in turn is a Division ofapplication Ser. No. 09/645,525 filed Aug. 25, 2000, now U.S. Pat. No.6,673,594. The disclosure of the prior applications is herebyincorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to an apparatus and method for perfusing one ormore organs to monitor, sustain and/or restore the viability of theorgan(s) and/or for transporting and/or storing the organ(s).

2. Description of Related Art

Preservation of organs by machine perfusion has been accomplished athypothermic temperatures with or without computer control withcrystalloid perfusates and without oxygenation. See, for example, U.S.Pat. Nos. 5,149,321, 5,395,314, 5,584,804, 5,709,654 and 5,752,929 andU.S. patent application Ser. No. 08/484,601 to Klatz et al., now U.S.Pat. No. 5,827,222, which are hereby incorporated by reference.Hypothermic temperatures provide a decrease in organ metabolism, lowerthe energy requirements, delay the depletion of high energy phosphatereserves and accumulation of lactic acid and retard the morphologicaland functional deterioration associated with disruption of blood supply.Oxygen can not be utilized efficiently by mitochondria belowapproximately 20° C. to produce energy, and the reduction incatalase/superoxide dismutase production and ascorbyl and glutathioneregeneration at low temperatures allows high free radical formation. Theremoval of oxygen from perfusates during low temperature machineperfusion has proven helpful in improving organ transplant results bysome investigators.

Reduction in potential oxygen damage is also accomplished via theaddition of antioxidants to the perfusate. In particular, this hasproven useful in reducing organ damage after long warm ischemia times.Numerous other perfusate additives have also been reported to improvethe outcome of machine perfusion.

Ideally organs would be procured in a manner that limits their warmischemia time to essentially zero. Unfortunately, in reality, manyorgans, especially from non-beating heart donors, are procured afterextended warm ischemia time periods (i.e., 45 minutes or more). Themachine perfusion of these organs at low temperature has demonstratedsignificant improvement (Transpl Int 1996 Daemen). Further, prior artteaches that the low temperature machine perfusion of organs ispreferred at low pressures (Transpl. Int 1996 Yland) with roller ordiaphragm pumps delivering the perfusate at a controlled pressure.Numerous control circuits and pumping configurations have been utilizedto achieve this objective and to machine perfuse organs in general. See,for example, U.S. Pat. Nos. 5,338,662 and 5,494,822 to Sadri; U.S. Pat.No. 4,745,759 to Bauer et al.; U.S. Pat. Nos. 5,217,860 and 5,472,876 toFahy et al.; U.S. Pat. No. 5,051,352 to Martindale et al.; U.S. Pat. No.3,995,444 to Clark et al.; U.S. Pat. No. 4,629,686 to Gruenberg; U.S.Pat. Nos. 3,738,914 and 3,892,628 to Thorne et al.; U.S. Pat. Nos.5,285,657 and 5,476,763 to Bacchi et al.; U.S. Pat. No. 5,157,930 toMcGhee et al.; and U.S. Pat. No. 5,141,847 to Sugimachi et al. However,in some situations the use of such pumps for machine perfusion of organsmay increase the risk of overpressurization of the organ should theorgan perfusion apparatus malfunction. High pressure perfusion (e.g.,above about 60 mm Hg) can wash off the vascular endothelial lining ofthe organ and in general damages organ tissue, in particular athypothermic temperatures where the organ does not have the neurologicalor endocrinal connections to protect itself by dilating its vasculatureunder high pressure.

Furthermore, the techniques used for assessment of the viability ofthese machine perfused organs have been a critical factor in limitingthe organs from greater use. While increased organ resistance (i.e.,pressure/flow) measurements during machine perfusion are a usefulindicator, they demonstrate only the worst case situations.

During low temperature machine perfusion of organs that have beendamaged by warm ischemia time or by the machine perfusion itself, theorgans will elute intracellular and endothelial as well as membraneconstituents. Over the years the appearance of various ubiquitousintracellular enzymes, such as lactic dehydrogenase (LDH) and alkalinephosphatase, in the perfusate has been used as a biomarker of organdamage. Recently, the determination of the presence of alphaglutathione-S-transferase (a-GST) and Pi glutathione-S-transferase(p-GST) in low temperature machine perfusion perfusates has proven asatisfactory indicator in predicting the functional outcome ofnon-beating heart donor kidney grafts before transplantation (Transpl1997 Daemen).

The prior art has also addressed the need to restore or maintain anorgan's physiological function after preservation for an extended periodof time at hypothermic temperatures. In particular, U.S. Pat. No.5,066,578 to Wikman-Coffelt discloses an organ preservation solutionthat contains large amounts of pyruvate. Wikman-Coffelt teaches thatflooding of the organ with pyruvate bypasses glycosis, the step in thecell energy cycle that utilizes adenosine triphosphate (ATP) to producepyruvate, and pyruvate is then available to the mitochondria foroxidative phosphorylation producing ATP. Wikman-Coffelt teachesperfusing or washing an organ at a warm temperature with a firstpreservation solution containing pyruvate for removal of blood or otherdebris from the organ's vessels and to vasodilate, increase flow andload the cells with an energy supply in the form of a clean substrate,namely the pyruvate. Wikman-Coffelt teaches that the pyruvate preventsedema, ischemia, calcium overload and acidosis as well as helps preservethe action potential across the cell membrane. The organ is thenperfused with a second perfusion solution containing pyruvate and asmall percentage of ethanol in order to stop the organ from working,vasodilate the blood vessels allowing for full vascular flow, continueto load the cells with pyruvate and preserve the energy state of theorgan. Finally the organ is stored in a large volume of the firstsolution for 24 hours or longer at temperatures between 4° C. and 10° C.

However, the mitochondria are the source of energy in cells and needsignificant amounts of oxygen to function. Organs naturally havesignificant pyruvate levels, and providing an organ with additionalpyruvate will not assist in restoring and/or maintaining an organ's fullphysiological function if the mitochondria are not provided withsufficient oxygen to function. Further, briefly flooding an organ withpyruvate may, in fact, facilitate tearing off of the vascularendothelial lining of the organ.

U.S. Pat. No. 5,599,659 to Brasile et al. also discloses a preservationsolution for warm preservation of tissues, explants, organs andendothelial cells. Brasile et al. teaches disadvantages of cold organstorage, and proposes warm preservation technology as an alternative.Brasile et al. teaches that the solution has an enhanced ability toserve as a medium for the culture of vascular endothelium of tissue, andas a solution for organs for transplantation using a warm preservationtechnology because it is supplemented with serum albumin as a source ofprotein and colloid; trace elements to potentiate viability and cellularfunction; pyruvate and adenosine for oxidative phosphorylation support;transferrin as an attachment factor; insulin and sugars for metabolicsupport and glutathione to scavenge toxic free radicals as well as asource of impermeant; cyclodextrin as a source of impermeant, scavenger,and potentiator of cell attachment and growth factors; a high Mg++concentration for microvessel metabolism support; mucopolysaccharides,comprising primarily chondroitin sulfates and heparin sulfates, forgrowth factor potentiation and hemostasis; and ENDO GRO™ as a source ofcooloid, impermeant and specific vascular growth promoters. Brasile etal. further teaches warm perfusing an organ for up to 12 hours at 30°C., or merely storing the organ at temperatures of 25° C. in thepreservation solution.

However, flooding an organ with such chemicals is insufficient to arrestor repair ischemic injury where the mitochondria are not provided withsufficient oxygen to function to produce energy. The oxygen needs of anorgan at more than 20° C. are substantial and cannot be met by a simplecrystalloid at reasonable flows. Further, assessment of the viability ofan organ is necessary before the use of any type of solution can bedetermined to have been fruitful.

WO 88/05261 to Owen discloses an organ perfusion system including anorgan chamber that is supplied with an emulsion fluid or physiologicalelectrolyte that is transported through a perfusion system. The chambercontains a synthetic sac to hold the organ. Perfusate enters the organthrough a catheter inserted into an artery. The perfusate is provided bytwo independent fluid sources; each of which includes two reservoirs.

SUMMARY OF THE INVENTION

The present invention focuses on avoiding damage to an organ duringperfusion while monitoring, sustaining and/or restoring the viability ofthe organ and preserving the organ for storage and/or transport. Theinvention is directed to an apparatus and method for perfusing an organto monitor, sustain and/or restore the viability of the organ and/or fortransporting and/or storing the organ. More particularly, the organperfusion apparatus and method according to the invention monitor,sustain and/or restore organ viability by perfusing the organ athypothermic temperature (hypothermic perfusion mode) and/or normothermictemperatures (normothermic perfusion mode) preferably after flushing ofthe organ such as by hypothermic flushing followed by static organstorage and/or organ perfusion at hypothermic temperatures for transportand/or storage of the organ.

The restoring of organ viability may be accomplished by restoring highenergy nucleotide (e.g., adenosine triphosphate (ATP)) levels and enzymelevels in the organ, which were reduced by warm ischemia time and/orhypoxia, by perfusing the organ with an oxygenated medical fluid, suchas an oxygenated cross-linked hemoglobin-based bicarbonate medicalfluid, at normothermic or near-normothermic temperatures. The organ maybe flushed with a medical fluid prior to perfusion with the oxygenatedmedical fluid. Such perfusion can be performed at either normothermic orhypothermic temperatures, preferably at hypothermic temperatures. Forhypothermic flush, static storage and hypothermic perfusion, the medicalfluid preferably contains little or no oxygen and preferably includesantioxidants, both molecular (e.g., 2-ascorbic acid tocopherol) andenzymatic (e.g., catalase and superoxide dismutase (SOD)). Normothermicand/or hypothermic perfusion, and preferably hypothermic perfusion, canbe performed in vivo as well as in vitro. Such perfusion arrestsischemic injury in preparation for transport, storage and/or transplantof the organ.

The normothermic treatment is preferably employed after an organ hasbeen subjected to hypothermic temperatures, statically and/or underperfusion. Such initial hypothermic exposure can occur, for example,during transport and/or storage of an organ after harvesting. Thetreatment is also suitable for organs that will ultimately be storedand/or transported under hypothermic conditions. In other words, thetreatment can be applied to organs prior to cold storage and/ortransport.

In the normothermic perfusion mode, gross organ perfusion pressure ispreferably provided by a pneumatically pressurized medical fluidreservoir controlled in response to a sensor disposed in an end oftubing placed in the organ, which may be used in combination with astepping motor/cam valve or pinch valve which provides for perfusionpressure fine tuning, prevents overpressurization and/or providesemergency flow cut-off. Alternatively, the organ may be perfuseddirectly from a pump, such as a roller pump or a peristaltic pump, withproper pump control and/or sufficiently fail-safe controllers to preventoverpressurization of the organ, especially as a result of a systemmalfunction. Substantially eliminating overpressurization preventsand/or reduces damage to the vascular endothelial lining and to theorgan tissue in general. Viability of the organ may be monitored,preferably automatically, in the normothermic perfusion mode, preferablyby monitoring organ resistance (pressure/flow) and/or pH, pO₂, pCO₂,LDH, T/GST, Tprotein, lactate, glucose, base excess and/or ionizedcalcium levels in the medical fluid that has been perfused through theorgan and collected.

An organ viability index may be provided taking into account the variousmeasured factors identified above, such as vascular resistance, pH etc.The index may be organ specific, or may be adaptable to various organs.The index compiles the monitored parameters into a diagnostic summary tobe used for making organ therapy decisions and deciding whether totransplant the organ. The index may be automatically generated andprovided to the physician.

Normothermic perfusion may be preceded by and/or followed by hypothermicperfusion. In the hypothermic mode, the organ is perfused with a medicalfluid containing substantially no oxygen, preferably a simplecrystalloid solution that may preferably be augmented with antioxidants,intermittently or at a slow continuous flow rate. Hypothermic perfusionalso can be performed in vivo as well as in vitro prior to removal ofthe organ from the donor. Hypothermic perfusion reduces the organ'smetabolic rate, allowing the organ to be preserved for extended periodsof time. The medical fluid is preferably fed into the organ by pressurefrom an intermediary tank which has a low pressure head sooverpressurization of the organ is avoided. Alternatively, inembodiments, gravity can be used to feed the medical fluid into theorgan from the intermediary tank, if appropriate. Alternatively, theorgan may be perfused directly from a pump, such as a roller pump or aperistaltic pump, with proper pump control and/or sufficiently fail-safecontrollers to prevent overpressurization of the organ, especially as aresult of a system malfunction. Substantially eliminatingoverpressurization prevents or reduces damage to the vascularendothelial lining of the organ and to the organ tissue in general, inparticular at hypothermic temperatures when the organ has less abilityto protect itself by vascular constriction. Viability of the organ mayalso be monitored, preferably automatically, during the recoveryprocess, preferably by monitoring organ resistance (pressure/flow)and/or pH, pO₂, pCO₂, LDH, T/GST, Tprotein, lactate, glucose, baseexcess and/or ionized calcium levels in the medical fluid that has beenperfused through the organ and collected.

Embodiments of this invention include a control system for automaticallycontrolling perfusion of one or more organs by selecting betweenperfusion modes and control parameters. Automatic perfusion may be basedon sensed conditions in the system or manually input parameters. Thesystem may be preprogrammed or programmed during use. Default values andviability checks are utilized.

The perfusion apparatus may be used for various organs, such as thekidneys, and may be adapted to more complex organs, such as the liver,having multiple vasculature structures, for example, the hepatic andportal vasculatures of the liver.

An organ diagnostic apparatus may also be provided to produce diagnosticdata such as an organ viability index. The organ diagnostic apparatusincludes features of an organ perfusion apparatus, such as sensors andtemperature controllers, as well as cassette interface features, andprovides analysis of input and output fluids in a perfusion system.Typically, the organ diagnostic apparatus is a simplified perfusionapparatus providing diagnostic data in a single pass, in-line perfusion.

The present invention also provides an organ cassette which allows anorgan to be easily and safely moved between apparatus for perfusing,storing, analyzing and/or transporting the organ. The organ cassette maybe configured to provide uninterrupted sterile conditions and efficientheat transfer during transport, recovery, analysis and storage,including transition between the transporter, the perfusion apparatusand the organ diagnostic apparatus.

The present invention also provides an organ transporter which allowsfor transportation of an organ over long distances. The organtransporter may be used for various organs, such as the kidneys, and maybe adapted to more complex organs, such as the liver, having multiplevasculature structures, for example, the hepatic and portal vasculaturesof the liver. The organ transporter includes features of an organperfusion apparatus, such as sensors and temperature controllers, aswell as cassette interface features.

The perfusion apparatus, transporter, cassette, and organ diagnosticapparatus may be networked to permit remote management, tracking andmonitoring of the location and therapeutic and diagnostic parameters ofthe organ or organs being stored or transported. The information systemsmay be used to compile historical data of organ transport and storage,and provide cross-referencing with hospital and United Network for OrganSharing (UNOS) data on the donor and recipient. The systems may alsoprovide outcome data to allow for ready research of perfusion parametersand transplant outcomes.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages of the invention will becomeapparent from the following detailed description of embodiments whentaken in conjunction with the accompanying drawings, in which:

FIG. 1 is an organ perfusion apparatus according to the invention;

FIG. 2 is a schematic diagram of the apparatus of FIG. 1;

FIG. 3 is a diagram of the electronics of the apparatus of FIG. 1;

FIG. 4 is an exploded view of a first pump module of a combined pump,filtration, oxygenation and/or debubbler apparatus according to theinvention;

FIG. 5 is an exploded view of a filtration module of a combined pump,filtration, oxygenation and/or debubbler apparatus according to theinvention;

FIG. 6 is an exploded view of an oxygenation module of a combined pump,filtration, oxygenation and/or debubbler apparatus according to theinvention;

FIG. 7 is an exploded view of a debubbler module of a combined pump,filtration, oxygenation and/or debubbler apparatus according to theinvention;

FIG. 8 is an exploded view of a second pump module of a combined pump,filtration, oxygenation and/or debubbler apparatus according to theinvention;

FIG. 9 is an exploded perspective view showing the modules of FIGS. 4-8assembled together;

FIG. 10 is a front perspective view of an assembled modular combinedpump, filtration, oxygenation and/or debubbler apparatus according tothe invention;

FIGS. 11A-11D show side perspective views of various embodiments of anorgan cassette according to the invention;

FIG. 12 is a schematic diagram of an organ perfusion apparatusconfigured to simultaneously perfuse multiple organs;

FIGS. 13A and 13B show a stepping motor/cam valve according to theinvention;

FIGS. 14A-14F show another stepping motor/cam valve according to theinvention;

FIG. 15 shows a block diagram that schematically illustrates a controlsystem according to the invention;

FIG. 16 shows an exemplary diagram of possible processing stepsaccording to the invention;

FIGS. 17 and 17A show an embodiment of an organ cassette of the presentinvention;

FIGS. 18 and 18A show an embodiment of an organ chair according to thepresent invention;

FIG. 19 shows an exterior perspective view of an organ transporteraccording to the present invention;

FIG. 20 shows a cross-section view of an organ transporter of FIG. 19;

FIG. 21 shows a block diagram of an organ transporter of FIG. 19;

FIG. 22 shows operation states of an organ transporter of FIG. 19;

FIG. 23 shows an alternative cross-section view of an organ transporterof FIG. 19;

FIG. 24 shows data structures and information transfer schemes of aperfusion and organ transplant system of the present invention;

FIGS. 25 and 25A show motor control of a perfusion pump according to thepresent invention;

FIG. 26 shows a liver perfusion apparatus according to the presentinvention;

FIG. 27 shows a close-up view of a peristaltic pump for use in aperfusion apparatus according to FIG. 26;

FIG. 28 shows an overall view of an organ diagnostic system according tothe present invention;

FIG. 29 shows a perspective view of an organ evaluation instrument foruse in an organ diagnostic system according to FIG. 28;

FIG. 30 shows an in-line perfusion system for use in an organ diagnosticsystem according to FIG. 28; and

FIG. 31 shows a logic circuit for an organ diagnostic system accordingto FIG. 28.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

For a general understanding of the features of the invention, referenceis made to the drawings. In the drawings, like reference numerals havebeen used throughout to designate like elements.

FIG. 1 shows an organ perfusion apparatus 1 according to the invention.FIG. 2 is a schematic illustration of the apparatus of FIG. 1. Theapparatus 1 is preferably at least partially microprocessor controlled,and pneumatically actuated. The microprocessor 150 connection to thesensors, valves, thermoelectric units and pumps of the apparatus 1 isschematically shown in FIG. 3. Microprocessor 150 and apparatus 1 may beconfigured to and are preferably capable of further being connected to acomputer network to provide data sharing, for example across a localarea network or across the Internet.

The organ perfusion apparatus 1 is capable of perfusing one or moreorgans simultaneously, at both normothermic and hypothermic temperatures(hereinafter, normothermic and hypothermic perfusion modes). All medicalfluid contact surfaces are preferably formed of or coated with materialscompatible with the medical fluid used, more preferably non-thrombogenicmaterials. As shown in FIG. 1, the apparatus 1 includes a housing 2which includes front cover 4, which is preferably translucent, and areservoir access door 3. The apparatus preferably has one or morecontrol and display areas 5 a, 5 b, 5 c, 5 d for monitoring andcontrolling perfusion.

As schematically shown in FIG. 2, enclosed within the housing 2 is areservoir 10 which preferably includes three reservoir tanks 15 a, 15 b,17. Two of the reservoir tanks 15 a, 15 b are preferably standard oneliter infusion bags, each with a respective pressure cuff 16 a, 16 b. Apressure source 20 can be provided for pressurizing the pressure cuffs16 a, 16 b. The pressure source 20 is preferably pneumatic and may be anon board compressor unit 21 supplying at least 10 LPM external cuffactivation via gas tubes 26,26 a,26 b, as shown in FIG. 2. Theinvention, however, is not limited to use of an on board compressor unitas any adequate pressure source can be employed, for example, acompressed gas (e.g., air, CO₂, oxygen, nitrogen, etc.) tank (not shown)preferably with a tank volume of 1.5 liters at 100 psi or greater forinternal pressurization. Alternatively, an internally pressurizedreservoir tank (not shown) may be used. Reservoir tanks 15 a, 15 b, 17may, in embodiments, be bottles or other suitably rigid reservoirs thatcan supply perfusate by gravity or can be pressurized by compressed gas.

Gas valves 22-23 are provided on the gas tube 26 to allow for control ofthe pressure provided by the onboard compressor unit 21. Anti-back flowvalves 24 a, 24 b may be provided respectively on the gas tubes 26 a, 26b. Pressure sensors P5, P6 may be provided respectively on the gas tubes26 a, 26 b to relay conditions therein to the microprocessor 150, shownin FIG. 3. Perfusion, diagnostic and/or transporter apparatus may beprovided with sensors to monitor perfusion fluid pressure and flow inthe particular apparatus to detect faults in the particular apparatus,such as pressure elevated above a suitable level for maintenance of theorgan. Gas valves GV₁ and GV₂ may be provided to release pressure fromthe cuffs 16 a, 16 b. One or both of gas valves GV₁ and GV₂ may bevented to the atmosphere. Gas valve GV₄ in communication with reservoirtanks 15 a, 15 b via tubing 18 a, 18 b may be provided to vent air fromthe reservoir tanks 15 a, 15 b through tubing 18. Tubing 18, 18 a, 18 b,26, 26 a and/or 26 b may be configured with filters and/or check valvesto prevent biological materials from entering the tubing or fromproceeding further along the fluid path. The check valves and/or filtersmay be used to prevent biological materials from leaving one organperfusion tubeset and being transferred to the tubeset of a subsequentorgan in a multiple organ perfusion configuration. The check valvesand/or filters may also be used to prevent biological materials, such asbacteria and viruses, from being transferred from organ to organ insubsequent uses of the perfusion apparatus in the event that suchbiological materials remain in the perfusion apparatus after use. Thecheck valves and/or filters prevent contamination problems associatedwith reflux in the gas and/or vent lines. For example, the valves may beconfigured as anti-reflux valves to prevent reflux. The third reservoirtank 17 is preferably pressurized by pressure released from one of thepressure cuffs via gas valve GV₂.

The medical fluid is preferably synthetic and may, for example, be asimple crystalloid solution, or may be augmented with an appropriateoxygen carrier. The oxygen carrier may, for example, be washed,stabilized red blood cells, cross-linked hemoglobin, pegolatedhemoglobin or fluorocarbon based emulsions. The medical fluid may alsocontain antioxidants known to reduce peroxidation or free radical damagein the physiological environment and specific agents known to aid intissue protection. As discussed in detail below, an oxygenated (e.g.,cross-linked hemoglobin-based bicarbonate) solution is preferred for thenormothermic mode while a non-oxygenated (e.g., simple crystalloidsolution preferably augmented with antioxidants) solution is preferredfor the hypothermic mode. The specific medical fluids used in both thenormothermic and hypothermic modes are designed to reduce or prevent thewashing away of or damage to the vascular endothelial lining of theorgan. For the hypothermic perfusion mode, as well as for flush and/orstatic storage, a preferred solution is the solution disclosed in U.S.patent application Ser. No. 09/628,311, filed Jul. 28, 2000, now U.S.Pat. No. 6,492,103, the entire disclosure of which is incorporatedherein by reference. Examples of additives which may be used inperfusion solutions for the present invention are also disclosed in U.S.Pat. No. 6,046,046 to Hassanein, the entire disclosure of which isincorporated by reference. Of course, other suitable solutions andmaterials may be used, as is known in the art.

The perfusion solution may be provided in a perfusion solution kit, forexample, a saleable package preferably containing at least one firstcontainer holding a first perfusion solution for normothermic perfusionand at least one second container holding a second, different perfusionsolution for hypothermic perfusion, optionally the box 10 shown in FIG.2. The first perfusion solution may contain at least one oxygen carrier,may be oxygenated and/or may be selected from the group consisting of across-linked hemoglobin and stabilized red blood cells. The secondperfusion solution may be non-oxygenated, may contain at least oneanti-oxidant, and/or may contain at least one vasodilator. Additionally,the solution preferably contains no more than 5 mM of dissolved pyruvatesalt. Also, the first container and the second container may beconfigured to be operably connected to a perfusion machine as perfusionfluid reservoirs in fluid communication with perfusate conduits of saidperfusion machine. Further, one of the first and second containers maybe compressible to apply pressure to the perfusion solution therein.Furthermore, at least one of the first and second containers may includea first opening for passage of a contained perfusion solution out of thecontainer and a second opening passage of a compressed gas into thecontainer. The package may be a cassette configured to be operablyconnected to a perfusion machine for connection of the first and secondcontainers within the cassette in fluid communication with perfusateconduits or tubing of the perfusion machine.

In other embodiments, the perfusion solution kit may contain at leastone first container holding a first perfusion solution for hypothermicperfusion at a first temperature and at least one second containerholding a second, different perfusion solution for hypothermic perfusionat a second temperature lower than the first temperature. In the kit,the first perfusion solution may contain at least a crystalloid and maycontain at least one vasodilator. The second perfusion solution may beoxygen carrier enhanced, where the oxygen carrier is selected from thegroup consisting of a hemoglobin and stabilized red blood cells. Inaddition, the second perfusion solution may, if desired, contain atleast one anti-oxidant or free radical scavenger. Preferably, the secondsolution contains no more than 5 mM of dissolved pyruvate salt. Asabove, the first container and the second container may be configured tobe operably connected to a perfusion machine as perfusion fluidreservoirs in fluid communication with perfusate conduits of saidperfusion machine. Further, one of the first and second containers maybe compressible to apply pressure to the perfusion solution therein.Furthermore, at least one of the first and second containers may includea first opening for passage of a contained perfusion solution out of thecontainer and a second opening passage of a compressed gas into thecontainer. The package may be a cassette configured to be operablyconnected to a perfusion machine for connection of the first and secondcontainers within the cassette in fluid communication with perfusateconduits or tubing of the perfusion machine.

The medical fluid within reservoir 10 is preferably brought to apredetermined temperature by a first thermoelectric unit 30 a in heattransfer communication with the reservoir 10. A temperature sensor T3relays the temperature within the reservoir 10 to the microprocessor150, which adjusts the thermoelectric unit 30 a to maintain a desiredtemperature within the reservoir 10 and/or displays the temperature on acontrol and display areas 5 a for manual adjustment. Alternatively or inaddition, and preferably where the organ perfusion device is going to betransported, the medical fluid within the hypothermic perfusion fluidreservoir can be cooled utilizing a cryogenic fluid heat exchangerapparatus such as that disclosed in co-pending application Ser. No.09/039,443, now U.S. Pat. No. 6,014,864, which is hereby incorporated byreference.

An organ chamber 40 is provided which supports a cassette 65, as shownin FIG. 2, which holds an organ to be perfused, or a plurality ofcassettes 65,65,65, as shown in FIG. 12, preferably disposed oneadjacent the other. Various embodiments of the cassette 65 are shown inFIGS. 11A-11D. The cassette 65 is preferably formed of a material thatis light but durable so that the cassette 65 is highly portable. Thematerial may also be transparent to allow visual inspection of theorgan.

Preferably the cassette 65 includes side walls 67 a, a bottom wall 67 band an organ supporting surface 66, which is preferably formed of aporous or mesh material to allow fluids to pass therethrough. Thecassette 65 may also include a top 67 d and may be provided with anopening(s) 63 for tubing (see, for example, FIG. 11D). The opening(s) 63may include seals 63 a (e.g., septum seals or o-ring seals) andoptionally be provided with plugs (not shown) to prevent contaminationof the organ and maintain a sterile environment. Also, the cassette 65may be provided with a closeable air vent 61 (see, for example, FIG.11D). Additionally, the cassette 65 may be provided with tubing forconnection to the organ or to remove medical fluid from the organ bathand a connection device(s) 64 for connecting the tubing to, for example,tubing 50 c, 81, 82, 91 and/or 132 (see, for example, FIG. 11D). Thecassette 65, and more particularly the organ support, opening(s),tubing(s) and/or connection(s), may be specifically tailored to the typeof organ and/or size of organ to be perfused. Outer edges 67 c of theside support walls 67 a can be used to support the cassette 65 disposedin the organ chamber 40. The cassette 65 may further include a handleportion 68 which allows the cassette 65 to be easily handled, as shown,for example, in FIGS. 11C and 11D. Each cassette 65 may also be providedwith its own stepping motor/cam valve 75 (for example, in the handleportion 68, as shown in FIG. 11C) for fine tuning the pressure ofmedical fluid perfused into the organ 60 disposed therein, discussed inmore detail below. Alternatively, pressure may, in embodiments, becontrolled by way of a pneumatic chamber, such as an individualpneumatic chamber for each organ (not shown), or by any suitablevariable valve such as a rotary screw valve or a helical screw valve.

FIG. 17 shows an alternative embodiment of cassette 65. In FIG. 17,cassette 65 is shown with tubeset 400. Tubeset 400 can be connected toperfusion apparatus 1 or to an organ transporter or an organ diagnosticapparatus, and allows cassette 65 to be moved between various apparatuswithout jeopardizing the sterility of the interior of cassette 65.Preferably, cassette 65 is made of a sufficiently durable material thatit can withstand penetration and harsh impact. Cassette 65 is providedwith a lid, preferably two lids, an inner lid 410 and an outer lid 420.The lids 410 and 420 may be removable or may be hinged or otherwiseconnected to the body of cassette 65. Clasp 405 provides a mechanism tosecure lids 410 and 420 to the top of cassette 65. Clasp 405 mayadditionally be configured with a lock to provide further security andstability. A biopsy port 430 may additionally be included in inner lid410 or both inner lid 410 and outer lid 420. Biopsy port 430 providesaccess to the organ to allow for additional diagnosis of the organ withminimal disturbance of the organ. Cassette 65 may also have an overflowtrough 440 (shown in FIG. 17A). Overflow trough 440 is a channel presentin the top of cassette 65. When lids 410 and 420 are secured on cassette65, overflow trough 440 provides a region that is easy to check todetermine if the inner seal is leaking. Perfusate may be poured into andout of cassette 65 and may be drained from cassette 65 through astopcock or removable plug.

Cassette 65 and/or both lids 410 and 420 may be constructed of anoptically clear material to allow for viewing of the interior ofcassette 65 and monitoring of the organ and to allow for video images orphotographs to be taken of the organ. Perfusion apparatus 1 or cassette65 may be wired and fitted with a video camera or a photographic camera,digital or otherwise, to record the progress and status of the organ.The captured images may be made available over a computer network suchas a focal area network or the Internet to provide for additional dataanalysis and remote monitoring. Cassette 65 may also be provided with atag that would signal, e.g., through a bar code, magnetism, radiofrequency, or other means, the location of the cassette, that thecassette is in the apparatus, and/or the identity of the organ to theperfusion apparatus or transporter. Cassette 65 may be sterile packagedand/or may be packaged or sold as a single-use disposable cassette, suchas in a peel-open pouch. A single-use package containing cassette 65 mayalso include tubeset 400.

Cassette 65 may additionally be provided with an organ chair 1800 shownin FIGS. 18 and 18A. Organ chair 1800 is removable and provides asupport surface for the organ within cassette 65. Utilizing a removableorgan chair 1800 allows the organ to be cannulated and secured undercold conditions when the organ is recovered from a donor before beingplaced into cassette 65. Organ chair 1800 may be reusable or single-use.Organ chair 1800 may be constructed specifically to correspond to eachtype of organ, such as the kidney, heart or liver. Organ chair 1800 ispreferably designed to be form fitting to the organ but to allow for thefull anthropometric range of organ sizes.

Preferably, organ chair 1800 is at least partially perforated to allowfluids to pass through organ chair 1800. The perforations in organ chair1800 may be sized to catch organ debris, or an additional filter layer,preferably constructed of cloth, fabric, nylon, plastic, etc., to catchorgan debris of at least 15 microns in diameter. In addition, a separatefilter may be used on the tubing that intakes fluid directly from theperfusate bath to prevent organ debris of a predetermined size, forexample at least 10 to 15 microns in diameter, from entering theperfusion tubing.

Organ chair 1800 may also be configured with a venous outflow sampler1810. Organ chair 1800 funnels the venous outflow into venous outflowsampler 1810. Venous outflow sampler 1810 provides a readily availablesource for capturing the venous outflow of the organ. Capturing thevenous outflow in this manner permits analysis of the perfusate leavingthe organ without cannulating a vein and enables organ viability to bemeasured with a high degree of sensitivity by analyzing differentiallythe perfusate flowing into and out of the organ. Alternatively, venousoutflow may be captured directly by cannulating a vein, but this methodincreases the risk of damaging the vein or the organ. Organ chair 1800may also be raised and lowered within cassette 65 to facilitate samplingfrom venous outflow sampler 1810. Alternatively, a sufficient amount ofthe organ bath may be drained from cassette 65 to obtain access tovenous outflow sampler 1810 or to capture venous outflow before theoutflow mixes with the rest of the perfusate in the organ bath.

Organ chair 1800 is preferably additionally configured with a cannula1820 that attaches to the perfused artery, such as the renal artery.Cannula 1820 may be reusable or may be suitable for single-use,preferably provided in a sterile package with cassette 65, organ chair1800 and tubeset 400. Cannula 1820 is provided with a cannula clamp 1830to secure cannula 1820 around the perfused artery and to preferablyprovide leak-tight perfusion. A straight-in flanged cannula may also beused, however clamping around the artery is preferable to preventcontact with the inner surface of the artery, which is easily damaged.Cannula 1820 may also be configured with additional branchingconnections for accessory arteries. Multiple cannula and cannula clampsizes may be used to accommodate various artery sizes or an adjustablecannula and cannula clamp may be used to accommodate various sizedarteries. Cannula clamp 1830 may be a clam-shell configuration or may bea two-part design. Cannula clamp 1830 may be configured with integral orseparate means for tightening cannula clamp 1830 to the proper pressureto provide leak-tight perfusion. In addition, cannula 1820 may beprovided with a snap 1840 to hold cannula 1820 closed. Cannula 1820 mayalso be provided with a vent 1850 to remove air bubbles from cannula1820.

Organ chair 1800 preferably has a detented region 1860 that correspondsto protrusions 1870 on cannula 1820. Such detents, tracks or grooves onorgan chair 1800 allow cannula 1820 to be positioned at severallocations to provide various tensions on the perfused artery. Thisallows the ideal minimum tension to be set for each artery. Cannulaclamp 1830 secures the perfusate tubing to the perfused artery. Cannula1820 is adjustably secured to organ chair 1800 to provide forpositioning the perfused artery to accommodate variations in organ sizeand artery length to prevent stretching, twisting, sagging or kinking ofthe artery. The combination of organ chair 1800, cannula 1820 andadditional straps or wide belts provides a secure platform to transportthe organ and to transfer the organ between the cassette and thesurgical field.

Organ chair 1800, cannula 1820 and/or cannula clamp 1830 may beconstructed of an optically clear material to facilitate monitoring ofthe organ and perfusion status.

The cassette 65 is configured such that it may be removed from the organperfusion apparatus 1 and transported to another organ perfusionapparatus in a portable transporter apparatus, such as, for example, aconventional cooler or a portable container such as that disclosed insimultaneously filed co-pending U.S. application Ser. No. 09/161,919,now U.S. Pat. No. 6,209,343, or U.S. Pat. No. 5,586,438 to Fahy, whichare hereby incorporated by reference in their entirety.

In embodiments, when transported, the organ is disposed on the organsupporting surface 66 and the cassette 65 is preferably enclosed in apreferably sterile bag 69, as shown, for example, in FIG. 11A. When theorgan is perfused with medical fluid, effluent medical fluid collects inthe bag 69 to form an organ bath. Alternatively, the cassette 65 can beformed with a fluid tight lower portion in which the effluent medicalfluid may collect, or the effluent medical fluid may collect in theorgan chamber 40 to form the organ bath. In either alternative case, thebag 69 would preferably be removed prior to inserting the cassette intothe organ chamber 40. Further, where a plurality of organs are to beperfused, an organ chamber may be provided for each organ.Alternatively, cassette 65 can be transported in the dual-lid cassetteof FIG. 17 and additionally carried within a portable organ transporter.

FIG. 19 shows an external view of an embodiment of transporter 1900 ofthe invention. The transporter 1900 of FIG. 19 has a stable base tofacilitate an upright position and handles 1910 for carrying transporter1900. Transporter 1900 may also be fitted with a shoulder strap and/orwheels to assist in carrying transporter 1900. A control panel 1920 ispreferably also provided. Control panel 1920 may displaycharacteristics, such as, but not limited to infusion pressure, poweron/off, error or fault condition, flow rate, flow resistance, infusiontemperature, bath temperature, pumping time, battery charge, temperatureprofile (maximums and minimums), cover open or closed, history log orgraph, and additional status details and messages, which are preferablyfurther transmittable to a remote location for data storage and/oranalysis. Flow and pressure sensors or transducers in transporter 1900may be used to calculate various organ characteristics including pumppressure and vascular resistance of an organ, which can be stored incomputer memory to allow for analysis of for example, vascularresistance history, as well as to detect faults in the apparatus, suchas elevated pressure.

Transporter 1900 has latches 1930 that require positive user action toopen, thus avoiding the possibility that transporter 1900 inadvertentlyopens during transport. Latches 1930 hold top 1940 in place ontransporter 1900. Top 1940 or a portion thereof may be constructed withan optically clear material to provide for viewing of the cassette andorgan perfusion status. Transporter 1900 may be configured with a coveropen detector that monitors and displays if the cover is open or closed.Transporter 1900 may be configured with an insulating exterior ofvarious thicknesses to allow the user to configure transporter 1900 forvarying extents and distances of transport. In embodiments, compartment1950 may be provided to hold patient and organ data such as charts,testing supplies, additional batteries, hand-held computing devicesand/or other accessories for use with transporter 1900. Transporter 1900may also be configured with means for displaying a UNOS label and/oridentification and return shipping information.

FIG. 20 shows a cross-section view of a transporter 1900. Transporter1900 contains cassette 65 and pump 2010. Cassette 65 may be placed intoand taken out of transporter 1900 without disconnecting tubeset 400 fromcassette 65, thus maintaining sterility of the organ. Sensors intransporter 1900 can detect the presence of cassette 65 in transporter1900, and depending on the sensor, can read the organ identity from abarcode or radio frequency or other smart tag that may be integral tocassette 65. This allows for automated identification and tracking ofthe organ and helps monitor and control the chain of custody. A globalpositioning system may be added to transporter 1900 and/or cassette 65to facilitate tracking of the organ. Transporter 1900 can be interfacedto a computer network by hardwire connection to a local area network orby wireless communication while in transit. This interface allowsperfusion parameters, vascular resistance, and organ identification andtransporter and cassette location to be tracked and displayed inreal-time or captured for future analysis.

Transporter 1900 also preferably contains a filter 2020 to removesediment and other particulate matter, preferably ranging in size from0.05 to 15 microns in diameter or larger, from the perfusate to preventclogging of the apparatus or the organ. Transporter 1900 also containsbatteries 2030, which may be located at the bottom of transporter 1900or beneath pump 2010 or at any other location that provides easy accessto change batteries 2030. Batteries 2030 may be rechargeable outside oftransporter 1900 or while intact within transporter 1900 and/or arepreferably hot-swappable one at a time. Batteries 2030 are preferablyrechargeable rapidly and without full discharge. Transporter 1900 mayalso provide an additional storage space 2040 at the bottom oftransporter 1900 for power cords, batteries and other accessories.Transporter 1900 may also include a power port for a DC hookup to avehicle such as an automobile or airplane and/or for an AC hookup.

FIG. 21 shows a block diagram of transporter 1900. Transporter 1900 ofFIG. 21 is intended to provide primarily hypothermic perfusion, and mayoperate at any temperatures, for example in the range of −25 to 60° C.,approximately 0 to 8° C., preferably approximately 4° C. The temperaturemay be adjusted based on the particular fluids used and adapted to theparticular transport details, such as length of time of transport.Transporter 1900 is cooled by coolant 2110, which may be an ice andwater bath or a cryogenic material. In embodiments using cryogenicmaterials, the design should be such that organ freezing is prevented.The temperature of the perfusate bath surrounding the organ is monitoredby temperature transducer 2115. Transporter 1900 also contains filters2020 to remove sediment and particulate, ranging in size from 0.05 to 15microns in diameter or larger, from the perfusate to prevent clogging ofthe apparatus or the organ. Using a filter 2020 downstream of pump 2010allows for capturing inadvertent pump debris and also dampens pressurespikes from pump 2010.

The flow of perfusate within transporter 1900 is controlled by pump2010, which is preferably a peristaltic or roller pump. Pump 2010 ispreferably not in contact with the perfusate to help maintain sterility.In addition, tubeset 400 may be attached to pump 2010 without openingthe tubing circuit. Pump 2010 is controlled by a computer ormicrocontroller. The computer can actively modulate the angular velocityof pump 2010 to reduce the natural pulse actions of pump 2010 to a lowlevel, resulting in essentially non-pulsatile flow. Further computercontrol can impose a synthesized pressure pulse profile that can besinusoidal or physiological or otherwise. The average flow rate andpressure can be made independent of pulse repetition rate by pulse widthmodulating or amplitude modulating the synthesized pressure pulses.Control over some or all of the pulse parameters can be made availableto users through control panel 1920 or over a network. Pulse control canbe organ specific. In the case of a liver, a single pump can providecontinuous flow to the portal vein at, for example, 1 to 3 liters perminute while providing pulsatile flow to the hepatic artery at, forexample, 100 to 300 ml per minute. Synchronizing the shunt valves to thepump controller allows independent pressure regulation of the two flows.

The flow of the perfusate into the organ is monitored by flow sensor2125. Pressure transducers 2120 may be present to monitor the pressurethe perfusate places on the tubing. Pressure transducers 2120 may beused to monitor the pump pressure and/or the infusion pressure. Apressure transducer 2120 may be present just upstream of the organ tomonitor the organ infusion pressure. Transporter 1900 may be configuredwith a bubble detector 2125 to detect bubbles before the perfusateenters bubble trap 2130. Bubble detectors, such as bubble detector 2125,may be used to detect bubbles in, for example, the infuse line and/or inthe pump output line. Bubble trap 2139 removes air bubbles from theperfusate and vents the bubbles into the wash tube. Bubble trap 2130 maybe disposable and may be constructed integral to tubeset 400. Perfusateexiting bubble trap 2130 can either continue through infuse valve 2140or wash valve 2150. Wash valve 2150 is normally open and infuse valve2140 is normally closed. Preferably, wash valve 2150 and infuse valve2140 operate dependently in an on/off manner, such that if one valve isopen, the other valve is closed. Although infuse valve 2140 is normallyclosed, if the sensor and monitors all report suitable perfusionparameters present in transporter 1900, then infuse valve 2140 may beopened to allow organ perfusion. In the occurrence of a fault, such aselevated perfusion pressure above a suitable level for the organ, infusevalve 2140 switches back to closed and wash valve 2150 is opened todivert fluid flow into the perfusate bath surrounding the organ. Thisprovides a failsafe mechanism that automatically shunts perfusate flowand prevents organ perfusion in case of a power failure or computer orelectronics malfunction. A pressure transducer 2120, such as designatedby P₂, may be hardwired, redundant to the computer and software control,to wash valve 2150 and infuse valve 2140 to quickly deliver a defaultmessage to the valves in the case of a pressure malfunction. Inembodiments, the diverted fluid may be separately collected in anothercontainer or compartment.

FIG. 22 shows various operation states of transporter 1900. For example,using the controls provided on control panel 1920, a user may selectoperations such as perfuse, idle, wash and prime. FIG. 22 shows variousoptions depending on the present state of transporter 1900. The labelsidle, prime, wash, perfuse and error handling indicate the state oftransporter 1900 that is preferably displayed on control panel 1920during the corresponding operation. For example, when transporter 1900is in a wash operation, control panel 1920 displays the wash operationindicator, such as an LED display. The arrows connecting the variousoperations of transporter 1900 indicate the manual and automatic actionsthat may occur to transition transporter 1900 between operation states.Manual actions require the user to act, for example by pressing a buttonor turning a knob or dial. FIG. 22 exemplifies pressing a button orother indicator, for example, to move from a perfusion operation to anidle operation by pressing the stop button (Press Stop). To movedirectly into a perfuse operation from an idle operation, a user pressesthe perfuse button (Press Perfuse).

Automatic operations may be controlled by the passage of time and/or byan internal monitor within transporter 1900. Such automatic operation isshown in FIG. 22, for example, connecting the prime operation to theidle operation. If the prime operation has been completed according tothe internal transporter program parameters before the wash button hasbeen pressed, transporter 1900 returns to an idle operation. Anotherautomatic operation occurs during a perfuse operation if a fault orerror occurs, such as overpressurization of the organ. When an error orfault occurs, transporter 1900 can move to an error handling operationto determine the extent or degree of the fault or error. If the fault orerror is determined to be a small or correctable error, transporter 1900moves into a wash operation. If transporter 1900 can then adjust thesystem parameters to handle the fault or error, transporter 1900 movesback to perfuse (Error Recovery). If transporter 1900 can not adjust thesystem parameters to handle the fault or error, transporter 1900 movesto an idle operation. If the error or fault detected is determined to besubstantial, transporter 1900 may move directly into an idle operation.

FIG. 23 shows an alternative cross-section of transporter 1900.Transporter 1900 may have an outer enclosure 2310 constructed of metal,or preferably a plastic or synthetic resin that is sufficiently strongto withstand penetration and impact. Transporter 1900 containsinsulation 2320, preferably a thermal insulation made of, for example,glass wool or expanded polystyrene. Insulation 2320 may be variousthicknesses ranging from 0.5 inches to 5 inches thick or more,preferably 1 to 3 inches, such as approximately 2 inches thick.Transporter 1900 is cooled by coolant 2110, which may be, e.g., an iceand water bath or a cryogenic material. In embodiments using cryogenicmaterials, the design should be such that organ freezing is prevented.An ice and water mixture is preferably in an initial mixture ofapproximately 1 to 1, however, in embodiments the ice and water bath maybe frozen solid. Transporter 1900 can be configured to hold variousamounts of coolant, preferably up to 10 to 12 liters. An ice and waterbath is preferable because it is inexpensive and can not get cold enoughto freeze the organ. Coolant 2110 preferably lasts for a minimum of 6 to12 hours and more preferably lasts for a minimum of 30 to 50 hourswithout changing coolant 2110. The level of coolant 2110 may be viewedthrough a transparent region of transporter 1900 or may be automaticallydetected and monitored by a sensor. Coolant 2110 can be replaced withoutstopping perfusion or removing cassette 65 from transporter 1900.Coolant 2110 is maintained in a watertight compartment 2115 oftransporter 1900. Compartment 2115 prevents the loss of coolant 2110 inthe event transporter 1900 is tipped or inverted. Heat is conducted fromthe walls of the perfusion reservoir and cassette 65 into coolant 2110enabling control within the desired temperature range. Coolant 2110 is afailsafe cooling mechanism because transporter 1900 automaticallyreverts to cold storage in the case of power loss or electrical orcomputer malfunction. Transporter 1900 may also be configured with aheater to raise the temperature of the perfusate.

Transporter 1900 may be powered by batteries or by electric powerprovided through plug 2330. An electronics module 2335 is also providedin transporter 1900. Electronics module 2335 is cooled by vented airconvection 2370, and may further be cooled by a fan. Preferably,electronic module 2335 is positioned separate from the perfusion tubesto prevent the perfusate from wetting electronics module 2335 and toavoid adding extraneous heat from electronics module 2335 to theperfusate. Transporter 1900 has a pump 2010 that provides pressure toperfusate tubing 2360 to deliver perfusate 2340 to organ 2350.Transporter 1900 may be used to perfuse various organs such as a kidney,heart, liver, small intestine and lung. Transporter 1900 and cassette 65may accommodate various amounts of perfusate 2340, for example up to 3to 5 liters. Preferably, approximately 1 liter of a hypothermicperfusate 2340 is used to perfuse organ 2350. Organ 2350 may be variousorgans, including but not limited to a kidney, heart, lung, liver orsmall intestine.

Cassette 65 and transporter 1900 are preferably constructed to fit ormate such that efficient heat transfer is enabled. The geometricelements of cassette 65 and transporter 1900 are preferably constructedsuch that when cassette 65 is placed within transporter 1900, theelements are secure for transport.

FIG. 24 shows various data structures and information connections thatcan be facilitated to assist in the overall communication and datatransfers that may be beneficial before, during and after organtransplantation. The perfusion apparatus, transporter, cassette, andorgan diagnostic apparatus may be networked to permit remote management,tracking and monitoring of the location and therapeutic and diagnosticparameters of the organ or organs being stored or transported. Theinformation systems may be used to compile historical data of organtransport and storage, and provide cross-referencing with hospital andUNOS data on the donor and recipient. The systems may also provideoutcome data to allow for ready research of perfusion parameters andtransplant outcomes. For example, information regarding the donor may beentered at the location where an organ is recovered from a donor.Information may also be directly recovered from the perfusion,diagnostic or transporter apparatus to monitor organ status andlocation. Various types of information may be grouped into sub-recordsor sub-directories to assist in data management and transfer. All thesub-records may be combined to form an overall transplant record, whichmay be disseminated to or retrievable by physicians, scientists or otherorganizations for tracking and monitoring purposes.

Preferred embodiments of transporter 1900 can automatically log much orall of the perfusion process data and transporter 1900 events into aninternal database. A radio frequency or barcode labeled tag or the likefor each cassette 65 allows transporter 1900 to reference the datauniquely to each organ. When transporter 1900 reaches a docking port,transporter 1900 can upload data to a main database computer over a LAN.Transporter 1900 can also provide real-time status whenever transporter1900 is connected to the LAN. Transporter 1900 can also be configuredwith a wireless communications setup to provide real-time data transferduring transport. Perfusion apparatus 1 can also be connected to the LANand since perfusion apparatus is generally stationary, data uploads canoccur continuously and in real-time. The data can be cross-referencedwith UNOS data to utilize the UNOS data on organ identification, donorcondition, donor logistics, recipient logistics and recipient outcomes.Data may be displayed and accessed on the Internet to facilitatemonitoring from any location.

Within the perfusion, diagnostic and/or transporter apparatus, the organbath is preferably cooled to a predetermined temperature by a secondthermoelectric unit 30 b, as shown in FIG. 2, in heat transfercommunication with the organ chamber 40. Alternatively and preferablywhere the organ perfusion device is going to be transported, the medicalfluid within reservoir 10 can be cooled utilizing a heat transfer devicesuch as an ice and water bath or a cryogenic fluid heat exchangerapparatus such as that disclosed in co-pending application Ser. No.09/039,443, now U.S. Pat. No. 6,014,864, which is hereby incorporated byreference. A temperature sensor T2 within the organ chamber 40 relaysthe temperature of the organ 60 to the microprocessor 150, which adjuststhe thermoelectric unit 30 b to maintain a desired organ temperatureand/or displays the temperature on the control and display areas 5 c formanual adjustment.

Medical fluid may be fed from the bag 15 a directly to an organ 60disposed in the organ chamber 40 through tubing 50 a,50 b,50 c or frombag 15 b through tubing 50 d,50 e,50 c by opening valve LV₄ or LV₃,respectively. Conventional medical fluid bag and tubing connections maybe utilized. All tubing is preferably disposable, easily replaceable andinterchangeable. Further, all tubing is preferably formed of or coatedwith materials compatible with the medical fluids used, more preferablynon-thrombogenic materials. An end of the tubing 50 c is inserted intothe organ 60. The tubing may be connected to the organ(s) withconventional methods, for example, with sutures. The tubing may includea lip to facilitate connection to the organ. Alternatively, cannula 1820described above may be used with or without connection to an organ chair1800. However, the specific methods and connection depend on the type oforgans(s) to be perfused.

The microprocessor 150 preferably controls the pressure source 20 inresponse to signals from the pressure sensor P1 to control the pressureof the medical fluid fed into the organ 60. The microprocessor 150 maydisplay the pressure on the control and display areas 5 a, optionallyfor manual adjustment. A fluid flow monitor F1 may also be provided onthe tubing 50 c to monitor the flow of medical fluid entering the organ60 to indicate, for example, whether there are any leaks present in theorgan.

Alternatively, the medical fluid may be fed from the reservoir tank 17via tubing 51 into an intermediary tank 70 preferably having a pressurehead of approximately 5 to 40 mm Hg. Medical fluid is then fed bygravity or, preferably, pressure, from the intermediary tank 70 to theorgan 60 along tubing 50 c by activating a valve LV₆. A level sensor 71may be provided in the intermediary tank 70 in order to maintain thepressure head. Where a plurality of organ chambers 40 and organs 60 areprovided, the organs 60 are connected in parallel to the reservoir 10utilizing suitable tubing duplicative of that shown in FIG. 2. See, forexample, FIG. 12. The use of pneumatically pressurized and gravity fedfluid pumps configured to avoid overpressurization even in cases ofsystem failure reduces or prevents general tissue damage to the organand the washing away of or damage to the vascular endothelial lining ofthe organ. Thus, organ perfusion in this system can be performed, e.g.,with either hydrostatic perfusion (gravity or pressure fed flow) orperistaltic perfusion by introducing flow to the organ from aperistaltic (roller) pump.

A bubble detection system may be installed to sense bubbles in theperfusate. An air sensor and sensor board are preferably used. Theoutput of the sensor activates a debubbler system, such as an opensolenoid valve, to rid bubbles from the perfusate flow prior to organintroduction. As with all of the sensors and detectors in this system,the bubble detector may be positioned at any point in the system that iseffective based on the particular parameters or design characteristicsof the system. For example, a bubble detector and debubbler system BDmay be positioned between the cam valve 205 and pressure sensor P1, asshown in FIG. 1.

A stepping motor/cam valve 205, or other suitable variable valve such asa rotary screw valve, may be arranged on the tubing 50 c to providepulsatile delivery of the medical fluid to the organ 60, to decrease thepressure of the medical fluid fed into the organ 60, and/or to stop flowof medical fluid into the organ 60 if the perfusion pressure exceeds apredetermined amount. Alternatively, a flow diverter or shunt line maybe provided in the perfusion apparatus to which the fluid flow isdiverted in the occurrence of a fault, such as excess pressure, forexample by opening and closing a valve or a series of valves. Specificembodiments of the stepping motor/cam valve are shown in FIGS. 13A-13Band 14A-14F. FIGS. 13A-13B show a stepping motor/rotational type camvalve.

FIG. 13A is a top view of the apparatus. Tubing, for example, tubing 50c, is interposed between a support 203 and cam 200. Cam 200 is connectedby a rod 201 to stepping motor 202. FIG. 13B is a side view of theapparatus. The dashed line shows the rotational span of the cam 200. InFIG. 13B, the cam 200 is in its non-occluding position. Rotated 180degrees, the cam 200 totally occludes the tubing 50 c with varyingdegrees of occlusion therebetween. This stepping motor/cam valve isrelatively fast, for example, with respect to the embodiment shown inFIGS. 14A-14F; however, it requires a strong stepping motor.

FIGS. 14A-14F disclose another stepping motor/cam valve 210 according tothe invention. FIG. 14A is a side view of the apparatus while FIG. 14Cis a top view. Tubing, for example, tubing 50 c, is interposed betweencam 220 and support 223. The cam 220 is connected to stepping motor 222by supports 221 a-221 d and helical screw 225, which is connected to thestepping motor 222 via plate 222 a. FIG. 14B shows the supports 221 aand plate 222 a in front view. As shown in FIG. 14D, where the support221 d is to the left of the center of the helical screw 225, the tubing50 c is not occluded. However, as the helical screw 225 is turned by thestepping motor 222, the support 221 d moves to the left (with respect toFIGS. 14D-14F) toward a position where the cam 220 partially or fullyoccludes the tubing 50 c. Such apparatus is slower than the apparatus ofFIGS. 13A-13B, but is more energy efficient.

Medical fluid expelled from the organ 60 which has collected in thebottom of the bag 69 (the cassette 65 or the organ chamber 40) is eitherpumped out through tubing 81 by a pump 80 for filtration, passingthrough a filter unit 82 and being returned to the organ bath, or ispumped out by a pump 90 for circulation through tubing 91. The pumps 80,90 are preferably conventional roller pumps or peristaltic pumps;however, other types of pumps may also be appropriate.

FIG. 25 shows a simplified schematic of a pump and pulse controller 2500and the interaction of the pump and pulse controller with a perfusionapparatus, such as shown in FIG. 1. Pump and pulse controller 2500receives pressure sensor data input 2510 from pressure sensor P andtachometer data input 2520. A tachometer may be used to set the phaseangle of the active wave. Pump and pulse controller 2500 converts thisinformation to motor drive output 2530, which powers pump 2540. FIG. 25Ashows various modes of operation that pump and pulse controller 2500 canprovide and how pump and pulse controller 2500 eliminates pressure pulsewaves from the perfusate flow and how it modulates perfusate flow ratewhile maintaining a constant pressure pulse rate.

A peristaltic pump driven at a constant speed provides a constantpressure wave in the associated tubing. FIG. 25A shows in the first modeof operation the waveforms that result from a constant drive speedapplied to a peristaltic pump. The second mode of operation, calledactive continuous, shows how the pressure pulse wave can be eliminatedor canceled out by applying a motor drive wave that is opposite to thepressure wave of the pump. In the third mode of operation, called activewaveform amplitude modulating, the pump pressure pulse wave is canceledby the motor drive wave, and a selected wave is added with a newamplitude as compared to the original pressure pulse wave amplitude. Inthe fourth mode of operation, called active waveform pulse widthmodulating, the pump pressure pulse wave is canceled by the motor drivewave, and a selected wave is added with a new pulse width as compared tothe original pressure pulse wave width. In an alternative mode ofoperation, the frequency may be modulated by adding a new frequency waveto the canceled waves.

A level sensor L2 in communication with the microprocessor 150 (see FIG.3) ensures that a predetermined level of effluent medical fluid ismaintained within the organ chamber 40. As shown in FIG. 2, atemperature sensor T1 disposed in the tubing 91 relays the temperatureof the medical fluid pumped out of the organ bath along tubing 91 to themicroprocessor 150, which monitors the same. A pressure sensor P2disposed along the tubing 91 relays the pressure therein to themicroprocessor 150, which shuts down the system if the fluid pressure inthe tubing 91 exceeds a predetermined limit, or activates an alarm tonotify the operator that the system should be shut down, for example, toclean filters or the like.

As the medical fluid is pumped along tubing 91 it preferably passesthrough a filter unit 95 (e.g., 25μ, 8μ, 2μ, 0.8μ, 0.2μ and/or 0.1μfilters); a CO₂ scrubber/O₂ membrane 100 and an oxygenator 110, forexample, a JOSTRAT™ oxygenator. The CO₂ scrubber/O₂ membrane 100 ispreferably a hydrophobic macroporous membrane with a hydrophilic (e.g.,Hypol) coating in an enclosure. A vacuum source (not shown) is utilizedto apply a low vacuum on a side opposite the hydrophilic coating by theactivation of valve VV₁. A hydrostatic pressure of approximately 100 mmHg is preferred for aqueous passage through the membrane. The mechanicalrelief valve (not shown) prevents the pressure differential fromattaining this level. Immobilized pegolated carbonic anhydrase may beincluded in the hydrophilic coating. This allows bicarbonate to beconverted to CO₂ and subsequently removed by vacuum venting. However,with organs such as kidneys which have the ability to eliminatebicarbonate, this may be unnecessary except in certain cases.

The oxygenator 110 is preferably a two stage oxygenator which preferablyincludes a hydrophilically coated low porosity oxygen permeablemembrane. A portion of the medical fluid is diverted around theoxygenator along tubing 111 in which is disposed a viability sensor V1,which senses fluid characteristics, such as organ resistance(pressure/flow), pH, pO₂, pCO₂, LDH, T/GST, Tprotein, lactate, glucose,base excess and ionized calcium levels indicative of an organ'sviability. The viability sensor V1 is in communication with themicroprocessor 150 and allows the organ's viability to be assessedeither automatically or manually. One of two gases, preferably 100%oxygen and 95/5% oxygen/carbon dioxide, is placed on the opposite sideof the membrane depending on the pH level of the diverted medical fluid.Alternatively, another pump (not shown) may be provided which pumpseffluent medical fluid out of the organ chamber 40 and through aviability sensor before returning it to the bath, or the viabilitysensor can be placed on tubing 81 utilizing pump 80. In embodiments, thefluid characteristics may be analyzed in a separate diagnostic apparatusand/or analyzer as shown in FIGS. 28-31.

The sensed fluid characteristics, such as organ resistance(pressure/flow), pH, pO₂, pCO₂, LDH, T/GST, Tprotein, lactate, glucose,base excess and ionized calcium levels may be used to analyze anddetermine an organ's viability. The characteristics may be analyzedindividually or multiple characteristics may be analyzed to determinethe effect of various factors. The characteristics may be measured bycapturing the venous outflow of the organ and comparing its chemistry tothe perfusate inflow. The venous outflow may be captured directly andmeasured or the organ bath may be measured to provide a roughapproximation of the fluid characteristics for comparisons over a periodof time.

In embodiments, an organ viability index is provided taking into accountthe various measured factors identified above, such as vascularresistance, pH, etc. The index may be organ specific, or may beadaptable to various organs. The index compiles the monitored parametersinto a diagnostic summary to be used for making organ therapy decisionsand deciding whether to transplant the organ. The index may beautomatically generated and provided to the physician. The index ispreferably computer generated via a connection to the perfusionapparatus, transporter, cassette and/or organ diagnostic apparatus. Theadditional information, such as donor specific information, may beentered into a single computer at the site of the perfusion apparatus,transporter, Cassette and/or organ diagnostic apparatus or may beentered in a remote computer and linked to the perfusion apparatus, etc.In embodiments, the index may be made available over a computer networksuch as a local area network or the Internet for quick comparison,remote analysis and data storage.

The organ viability index provides measurements and normal ranges foreach characteristic, such as vascular resistance and perfusate chemistrycharacteristics based on pH, pO₂, pCO₂, LDH, T/GST, Tprotein, lactate,glucose, base excess and ionized calcium levels. For example, atapproximately 5° C., normal pH may be from 7.00 and 8.00, preferablyfrom 7.25 and 7.75 and more preferably from 7.50 and 7.60 and baseexcess may be in the range of from −10 to −40, preferably from −15 to−30, and more preferably from −20 to −25. Measurements that are outsidethe normal range may be indicated visually, e.g., by an asterisk orother suitable notation, aurally or by machine perceivable signals. Thecharacteristics give the physician insight into the metabolism of theorgan, such as stability of the metabolism, consumption of glucose,creation of lactic acid and oxygen consumption.

The index may also provide identifying information, such as age, gender,blood type of the donor and any expanded criteria; organ information,such as organ collection date and time, warm ischemia time, coldischemia time and vascular resistance; apparatus information, such asflow rate, elapsed time the pump has been operating and pressure; andother identifiers such as UNOS number and physician(s) in charge. Theindex may additionally provide temperature corrections if desired.

Returning to FIG. 2 and the flow and/or treatment of the medical fluidor perfusate in perfusion apparatus 1, alternative to the pump 90,filter unit 95, the CO₂ scrubber/O₂ membrane 100 and/or the oxygenator110, a modular combined pump, filtration, oxygenation and/or debubblerapparatus may be employed such as that described in detail insimultaneously filed co-pending U.S. patent application Ser. No.09/039,318, which is hereby incorporated by reference. As shown in FIGS.4-10, the apparatus 5001 is formed of stackable modules. The apparatus5001 is capable of pumping a fluid through a system as well asoxygenating, filtering and/or debubbling the fluid. The modules are eachformed of a plurality of stackable support members and are easilycombinable to form a compact apparatus containing desired components.Filtration, oxygenation and/or degassing membranes are disposed betweenthe support members.

FIGS. 4-8 show various modules that may be stacked to form a combinedpump, filtration, oxygenation and/or debubbler apparatus, such as thecombined pump, filtration, oxygenation and debubbler apparatus 5001shown in FIGS. 9-10. As depicted in these figures, the combined pump,filtration, oxygenation and debubbler apparatus 5001 is preferablyformed of a plurality of stackable support members groupable to form oneor more modules.

Interposed between the plurality of stackable support member arefiltration, oxygenation and/or degassing membranes depending on aparticular user's needs. The filtration, oxygenation and/or degassingmembranes are preferably commercially available macro-reticularhydrophobic polymer membranes hydrophilically grafted in a commerciallyknown way, such as, for example, ethoxylation, to prevent proteindeprivation, enhance biocompatibility with, for example, blood and toreduce clotting tendencies. The filtration membrane(s) is preferablyhydrophilically grafted all the way through and preferably has aporosity (pore size) within a range of 15 to 35μ, more preferably 20 to30μ, to filter debris in a fluid, preferably without filtering outcellular or molecular components of the fluid. The degassing membrane(s)and oxygenation membrane(s) are hydrophilically surface treated tomaintain a liquid-gas boundary. The degassing membrane(s) andoxygenation membrane(s) preferably have a porosity of 15μ or less, morepreferably 10μ or less.

The modules may include a first pump module 5010, as shown in explodedview in FIG. 4; a filtration module 5020, as shown in exploded view inFIG. 5; an oxygenation module 5030, as shown in exploded view in FIG. 6;a debubbler module 5040, as shown in exploded view in FIG. 7; and asecond pump module 5050, as shown in exploded view in FIG. 8. The pumpmodules are each connected to a source of pump fluid and are actuatedeither manually or by the microprocessor. The support members arepreferably similarly shaped. For example, the support members may eachbe plate-shaped; however, other shapes may also be appropriate. As shownin FIG. 10, the support members are preferably removably connected byscrews or bolts 5065; however, other fasteners for assembling theapparatus may also be appropriate.

The first pump module 5010 preferably includes a first (end) supportmember 5011, a second support member 5012 with a cut-out center area5012 c, a diaphragm 5013 and a third support member 5014. The supportmembers of this module and each of the other modules are preferably thinand substantially flat (plate-like), and can be formed of anyappropriate material with adequate rigidity and preferably alsobiocompatibility. For example, various resins and metals may beacceptable. A preferred material is an acrylic/polycarbonate resin.

The first (end) support member 5011 is preferably solid and providessupport for the pump module 5010. The first (end) support member 5011preferably includes a domed-out cavity for receiving pump fluid such asair. Tubing 5011 t is provided to allow the pump fluid to enter the pumpmodule 5010. The diaphragm 5013 may be made of any suitable elastic andpreferably biocompatible material, and is preferably polyurethane. Thethird support member 5014 includes a domed-out fluid cavity 5014 d andtubing 5014 t for receiving fluid, such as, for example, blood or anartificial perfusate, into the cavity 5014 d of the pump module 5010.The first pump module, or any of the other modules, may also include aport 5014 p for sensors or the like. Preferably hemocompatibleanti-backflow valves serve to allow unidirectional flow through the pumpmodule 5010.

The filtration module 5020 preferably includes a filtration membrane5021 m which forms a boundary of cavity 5014 d, a first support member5022 with a cut-out center area 5022 c, a degassing membrane 5022 m andsecond and third support members 5023 and 5024. The filtration membrane5021 m is preferably a 25μ macro-reticular filtration membrane modifiedto enhance biocompatibility with, for example, blood and to reduceclotting tendencies (like the other supports, filters and membranes inthe device). The degassing membrane 5022 m is preferably a 0.2-3μmacro-reticular degassing membrane with a reverse flow aqueous pressuredifferential of at least 100 mmHg for CO₂ removal surface modified toenhance biocompatibility.

The first support 5022 includes tubing 5022 t for forwarding fluid intothe oxygenation module 30, or another adjacent module, if applicable,after it has passed through the filtration membrane 5021 m and along thedegassing membrane 5022 m. The second support member 5023 of thefiltration module 5020 includes a domed-out fluid cavity 5023 d andtubing 5023 t through which a vacuum may be applied to the cavity 5023 dto draw gas out of the fluid through degassing membrane 5022 m. Thefourth support member 5024 is preferably solid and provides support forthe filtration module 5020. The third support member can also includetubing 5024 t through which a vacuum may be applied to draw gas out ofthe fluid through the degassing membrane 5031 m of the oxygenationmodule 5030 as discussed below. The filtration module 5020, or any ofthe other modules, may also include a port 5023 p for sensors or thelike.

The oxygenation module 5030 includes a degassing membrane 5031 m, afirst support member 5032, a filtration membrane 5033 m, an oxygenationmembrane 5034 m, a second support member 5034 with a cut-out center area5034 c, and third and fourth support members 5035, 5036. The degassingmembrane 5031 m is preferably a 0.2-3μ macro-reticular degassingmembrane with a reverse flow aqueous pressure differential of at least100 mmHg surface modified to enhance biocompatibility.

The first support member 5032 includes a domed-out fluid cavity 5032 d.The surface of the domed-out fluid cavity 5032 d preferably forms atortuous path for the fluid, which enhances the oxygenation anddegassing of the fluid. The filtration membrane 5033 m is preferably a25μ macro-reticular filtration membrane modified to enhancebiocompatibility. The oxygenation membrane 5034 m is preferably a 0.2-1μmacro-reticular oxygenation membrane with a reverse flow aqueouspressure differential of at least 100 mmHg surface modified to enhancebiocompatibility.

The second support member 5034 includes tubing 5034 t for forwardingfluid out of the oxygenation module 5030 into the debubbler module 5040,or another adjacent module, if applicable. The third support member 5035includes a domed-out cavity 5035 d and tubing 5035 t for receivingoxygen from an external source. The fourth support member 5036 ispreferably solid and provides support for the oxygenation module 5030.

The debubbler module 5040 includes a first support member 5041, afiltration membrane 5042 m, a degassing membrane 5043 m, a secondsupport member 5043 having a cut-out center area 5043 c, and a thirdsupport member 5044. The first support member 5041 has a domed-out fluidcavity 5041 d.

The filtration membrane 5042 m is preferably a 25μ macro-reticularfiltration membrane modified to enhance biocompatibility. The degassingmembrane 5043 m is preferably a 0.2-3μ macro-reticular degassingmembrane with a reverse flow aqueous pressure differential of at least100 mmHg surface modified to enhance biocompatibility. The secondsupport member 5043 has tubing 5043 t for forwarding fluid out of thedebubbler module 5040 into the pump module 5050, or another adjacentmodule, if applicable. The third support member 5044 includes adomed-out cavity 5044 d and tubing 5044 t through which a vacuum may beapplied to draw gas out of the fluid through the degassing membrane 5043m.

The second pump module 5050 may correspond to the first pump module5010. It preferably includes a first support member 5051, a diaphragm5052, a second support member 5053 with a cut-out center area 5053 c,and a third (end) support member 5054. The first support member 5051includes a domed out fluid cavity 5051 d and tubing 5051 t for allowingfluid to exit the pump module. The diaphragm 5052 is preferably apolyurethane bladder.

The third (end) support piece member 5054 is preferably solid andprovides support for the pump module 5050. Support member 5054preferably includes a domed out cavity (not shown) for receiving pumpfluid. Tubing 5054 a is provided to allow the pump fluid such as air toenter the pump module 5050. Preferably hemocompatible anti-backflowvalves may serve to allow unidirectional flow through the pump module5050.

In operation, blood and/or medical fluid enters the first pump module5010 through tube 5014 t passes through the filtration membrane 5021 mand along the degassing membrane 5022 m. A small vacuum is appliedthrough tubing 5023 t to draw gas through the degassing membrane 5022 m.Next, the blood and/or medical fluid travels into the oxygenation module5030 via internal tubing 5022 t, passing along the degassing membrane5031 m, through the filtration membrane 5033 m and along the oxygenationmembrane 5034 m. Oxygen is received into the domed-out cavity 5035 d ofthe third support member of the oxygenation module 5030 via tubing 5035t and passes through the oxygenation membrane 5034 m into the bloodand/or medical fluid as the blood and/or medical fluid travels along itssurface.

After being oxygenated by the oxygenation module 5030, the blood and/ormedical fluid then travels via internal tubing 5034 t into the debubblermodule 5040. The blood and/or medical fluid passes through thefiltration membrane 5042 m and along the degassing membrane 5043 m. Asmall vacuum force is applied through tubing 5044 t to draw gas out ofthe blood and/or medical fluid through the degassing membrane 5043 m.After passing through the degassing module 5040, the blood and/ormedical fluid travels into the second pump module 5050 through tubing5041 t, and exits the second pump module 5050 via tubing 5051 t.

After passing through the oxygenator 110, or alternatively through thecombined pump, oxygenation, filtration and/or degassing apparatus 5001,the recirculated medical fluid is selectively either directed to thereservoir 15 a or 15 b not in use along tubing 92 a or 92 b,respectively, by activating the respective valve LV₂ and LV₅ on thetubing 92 a or 92 b, or into the organ chamber 40 to supplement theorgan bath by activating valve LV₁. Pressure sensors P3 and P4 monitorthe pressure of the medical fluid returned to the bag 15 a or 15 b notin use. A mechanical safety valve MV₂ is provided on tubing 91 to allowfor emergency manual cut off of flow therethrough. Also, tubing 96 andmanual valve MV, are provided to allow the apparatus to be drained afteruse and to operate under a single pass mode in which perfusate exitingthe organ is directed to waste rather than being recirculated(recirculation mode.)

A bicarbonate reservoir 130, syringe pump 131 and tubing 132, and anexcretion withdrawal unit 120, in communication with a vacuum (notshown) via vacuum valve VV₂, and tubing 121 a, 122 a are also eachprovided adjacent to and in communication with the organ chamber 40.

The present invention also provides for perfusion apparatus adapted fororgans with complex vasculature structures, such as the liver. Using theliver as an example, FIG. 26 shows perfusion apparatus 2600. Perfusionapparatus 2600 has a single pump 2610, which is preferably a roller pumpor peristaltic pump. The tubing splits into two or more directions with,for example, three tubes going toward the portal vein side of the liver(portal tubing 2625) and one tube going toward the hepatic artery sideof the liver (hepatic tubing 2626). The portal side of perfusionapparatus 2600 has more tubes because the portal side of the liver usesthree to ten times the flow that the hepatic side uses. FIG. 27 shows aperspective view of pump 2610 and the tubing split into portal tubing2625 and hepatic tubing 2626.

Both the portal side and the hepatic side of perfusion apparatus 2600preferably have a filter 2630, bubble trap 2640, pressure transducer2650, temperature transducer 2660, and flow sensor 2670. An additionaltemperature transducer 2660 may be present in fluid return tubing 2620.The organ may be cooled as discussed above, for example by an ice andwater bath 2680 or by a cryogenic fluid. In embodiments using cryogenicfluids, the design should be such that organ freezing is prevented.

Multiple pumps may be used (as shown in FIG. 26); however, utilizingmultiple pumps generally increases the size and cost of the apparatus.Utilizing a single pump 2610 for both vasculature systems provides avariety of modes that can be used to perfuse a liver. After each bubbletrap 2640, the tubing splits into two directions. On the hepatic side,hepatic infusion valve 2685 controls the flow to the hepatic side of theliver and hepatic wash valve 2686 controls the flow into the organ bath.On the portal side, portal infusion valve 2695 controls the flow to theportal side of the liver and portal wash valve 2696 controls the flowinto the organ bath. Preferably, each pair of infusion valves and washvalves operates in an on/off or either/or manner. In other words, when,for example, the portal side is set to infuse, the portal wash valve2696 is closed. The following table shows various modes of operation forperfusion apparatus 2600.

MODES OF PORTAL HEPATIC DOMINANT OPERATION VALVES VALVES PRESSURE NOTESPortal Only Infuse Wash Portal No hepatic perfusion Portal PriorityInfuse Infuse Portal Hepatic slave to portal Hepatic Only Wash InfuseHepatic No portal perfusion Hepatic Priority Infuse Infuse HepaticPortal slave to hepatic Alternating Infuse Switching Alternating Wavyportal flow; pulsed hepatic flow

The modes of operation identified in the table above show options forinfusing a liver. In the first mode, Portal Only, the portal side of theliver is infused. Therefore, the portal valves are set to infuse, whichmeans that portal infusion valve 2695 is open and portal wash valve 2696is closed. Also, in a Portal Only mode, hepatic infusion valve 2685 isclosed and hepatic wash valve 2686 is open. In a Portal Only mode, theportal pressure is dominant, which means the pressure is controlled bythe pressure transducer 2650 on the portal side. In this mode, there isno hepatic infusion.

In a Portal Priority mode, the portal valves and the hepatic valves areset to infuse. The portal pressure is dominant; and therefore, thehepatic side is a slave to the portal side. In an Alternating mode, theportal valves are set to infuse and the hepatic valves switch between aninfuse setting and a wash setting. In an Alternating mode, when thehepatic valves are set to infuse, the hepatic side provides the dominantpressure. When the hepatic valves are set to wash, the portal sideprovides the dominant pressure. This type of alternating pressurecontrol provides the portal side with a wavy flow and provides thehepatic side with a pulsed flow.

The present invention also provides an organ diagnostic system 2800shown in FIG. 28. Organ diagnostic system 2800 has a computer 2810 andan analyzer 2820. Connected to both computer 2810 and analyzer 2820 isan organ evaluation instrument 2830, also shown in FIG. 29. Organdiagnostic system 2800 is preferably provided with suitable displays toshow the status of the system and the organ. Organ evaluation instrument2830 has a perfusate chamber 2840 and an organ chamber 2850. Connectinganalyzer 2820 and organ evaluation instrument 2830 is a transfer line2860. Organ diagnostic system 2800 provides analysis of an organ andproduces an organ viability index quickly and in a sterile cassette,preferably transferable from perfusion apparatus 1 and/or transporter1900. The organ viability index is preferably produced by flow andtemperature programmed single-pass perfusion and in-line automaticanalysis. The analysis may be performed in a multi-pass system, althougha beneficial aspect of the single-pass system is that it can beconfigured with a limited number of sensors and requires only enoughperfusate to perform the analysis. Single-pass perfusion also allows foran organ inflow with a perfusate having a known and predeterminedchemistry. This increases the flexibility of types and contents ofperfusates that may be delivered, which can be tailored and modified tothe particular analysis in process.

FIG. 29 shows a perspective view of organ evaluation instrument 2830.Organ evaluation instrument 2830 has a perfusate chamber 2840 and anorgan chamber 2850. Organ chamber 2850 may be insulated and preferablyhas a lid 2910 that may be removable or may be hinged. Organ chamber2850 is preferably configured to receive cassette 65, preferably withoutopening cassette 65 or jeopardizing the sterility of the interior ofcassette 65. Cassette 65 and organ chamber 2850 are preferablyconstructed to fit or mate such that efficient heat transfer is enabled.The geometric elements of cassette 65 and organ chamber 2850 arepreferably constructed such that when cassette 65 is placed within organchamber 2850, the elements are secure for analysis. A port 2920 is alsoprovided to connect transfer line 2860.

FIG. 30 shows a single-pass fluid system of organ diagnostic system2800. The initial perfusion fluids 3000 are contained in a chamber 3010.Chamber 3010 is preferably temperature controlled by a heating andcooling system. Fluid flow within the system is monitored by flow sensor3020 and controlled by signaling to pinch valves 3030 and pumps 3040.The fluid system also provides a bubble trap 3050, a pressure transducer3060 and a temperature transducer 3070. Heat exchanger 3080 providestemperature control and heating and cooling to the fluid within thesystem prior to organ perfusion. The organ is perfused in cassette 65.The fluid in the organ bath may be collected, or the venous outflow maybe captured, to be analyzed. The fluid is collected and passed viatransfer line 2860 to analyzer 2820. Transfer line 2860 may also beprovided with a separate heating and cooling unit. After the fluid isanalyzed, it may be collected in a waste receptacle 3090.

FIG. 31 shows a logic circuit for organ diagnostic system 2800. Thecomputer provides control parameters and receives results and data fromthe analyzer. The logic circuit shows inputs from the sensors to themicrocontroller and outputs to hardware elements, such as perfusatecoolers, perfusate heaters, pinch valves, pumps, transferlineheater/cooler and displays.

The method according to the invention preferably utilizes apparatus suchas that discussed above to perfuse an organ to sustain, monitor and/orrestore the viability of an organ and/or to transport and/or store theorgan. Preservation of the viability of an organ is a key factor to asuccessful organ transplant. Organs for transplant are often deprived ofoxygen (known as ischemia) for extended periods of time due to diseaseor injury to the donor body, during removal of the organ from the donorbody and/or during storage and/or transport to a donee body. Theperfusion, diagnostic, and/or transporter apparatus of the presentinvention have the ability to detect the cell chemistry of an organ tobe transplanted in order to adjust the perfusate and control thecellular metabolism to repair ischemic damage to the organ and toprevent reperfusion injury. One specific outcome of ischemic injury maybe apoptosis or programmed cell death. Specific agents and additivesprovided to an organ by the perfusion, diagnostic and/or transporterapparatus, under conditions controlled by the particular apparatus, mayinterrupt, decrease and/or reverse apoptosis.

In preferred methods of the present invention, an organ or tissue istreated ex vivo by mechanical, physical, chemical or geneticmanipulation and/or modification to treat disease and/or treat damage toand/or enhance the properties of the organ or tissue. An organ or tissuesample may be removed from a first body, modified, treated and/oranalyzed outside the first body and either returned to the first body ortransplanted to a second body. An advantage of the apparatus is that itenlarges the time that an organ may be available for ex vivo treatment,e.g., for hours (e.g. 2, 4, 6, 8, 10, 12 or more hours) or even days(e.g. 2, 4, 6, 8, 10, 12 or more days) or weeks (e.g. 1, 2, 3, 4, 5, 6,7, 8 or more weeks). In preferred embodiments, the perfusion, diagnosticand/or transporter apparatus of the present invention may be used toprovide particular solutions or chemicals to an organ or tissue or maybe used to perform particular treatments including flushing or washingan organ or tissue with particular solutions or chemicals. Ex vivotreatments may be performed on tissue or an organ to be transplanted ormay be performed on tissue or an organ that has been removed from apatient and is to be returned to the patient after the desired procedureis performed. Ex vivo treatments include but are not limited totreatment of tissue or an organ that has endured a period or periods ofischemia and/or apoxia. Ex vivo treatments may involve performingsurgical techniques on an organ, such as cutting and suturing an organ,for example to remove necrotic tissue. Any surgical or other treatmenttechnique that may be performed on tissue or an organ in vivo may alsobe performed on tissue or an organ ex vivo. The benefit of such ex vivotreatment may be seen, for example, in the application of radiation orchemotherapy to treat a tumor present in or on an organ, to preventother portions of the patient from being subjected to extraneousradiation or chemotherapy during treatment. The perfusion andtransporter apparatus of the present invention also provide additionaltime for a physician to maintain the tissue or organ before, duringand/or after performing a particular technique on the tissue or organ.

Particles trapped in an organ's vasculature may prevent the organ fromperfusing properly, or may cause the organ to function improperly,before and/or after transplantation. Perfusion, diagnostic andtransporter apparatus of the invention provide ex vivo techniquesinclude perfusing, flushing or washing an organ with suitable amounts ofa thrombolytic agent, such as streptokinase, to dissolve blood clotsthat have formed or to prevent the formation of blood clots in an organand to open the vasculature of the organ. Such techniques are disclosed,for example, in U.S. Provisional Patent Application No. 60/227,843, nowabandoned, the entire disclosure of which is hereby incorporated byreference.

Another concern with organ transplantation is the degree to which arecipient may be medicated to prevent organ rejection. In organtransplantation, a further ex vivo technique involves modifying theorgan to avoid having it activate the immune system of the donee toprevent or reduce organ rejection and to limit or prevent the need tosuppress the donee's immune system before, during and/or after organtransplantation so as to increase the tolerance of the donee to thetransplanted organ. Modifications of an organ may, for example,encourage the donee body to recognize the transplanted organ asautologous. The perfusion, diagnostic and/or transporter apparatus ofthe present invention may deliver substances such as chemical compounds,natural or modified antibodies, immunotoxins or the like, to an organand may assist the organ to adsorb, absorb or metabolize such substancesto increase the likelihood that the organ will not be rejected. Thesesubstances may also mask the organ by blocking, killing, depletingand/or preventing the maturation of allostimulatory cells (dendriticcells, passenger leukocytes, antigen presenting cells, etc.) so that therecipient's immune system does not recognize it or otherwise recognizesthe organ as autologous. An organ may be treated just prior totransplantation or may be pretreated hours, days or weeks beforetransplantation. Such techniques are further described in U.S.Provisional Patent Application No. 60/227,841, now abandoned, the entiredisclosure of which is hereby incorporated by reference.

Substances, such as modified or unmodified immunoglobulin, steroidsand/or a solution containing polyethylene glycol (PEG) and anantioxidant such as glutathione, may also be provided to an organ ortissue to mask the organ or to treat the onset of intimal hyperplasiaduring cryopreservation and/or organ or tissue transplantation. Thesesolutions may be provided to an organ or tissue by perfusion, diagnosticand/or transporter apparatus of the invention. Exemplary such solutionsand methods are disclosed in U.S. patent application Ser. No.09/499,520, now U.S. Pat. No. 6,280,925, the entire disclosure of whichis hereby incorporated by reference.

The perfusion, diagnostic and transporter apparatus of the invention maybe used in conjunction with the above techniques and methods and/or inconjunction with further techniques and methods, to perform research onan organ or tissue. The various apparatus may enlarge the time that anorgan may be available for ex vivo treatment, e.g., for hours (e.g. 2,4, 6, 8, 10, 12 or more hours) or even days (e.g. 2, 4, 6, 8, 10, 12 ormore days) or weeks (e.g. 1, 2, 3, 4, 5, 6, 7, 8 or more weeks). Duringthe period in which the organ is preserved and/or maintained, variousdrug research and development may be performed on and/or with the organ.Further treatments may be performed for research purposes, such asdeveloping immunomodification parameters. Since the organ or tissue maybe maintained and/or analyzed at or near physiologic parameters, anorgan may be tested for the effects of various treatments and/orsubstances on the organ or tissue ex vivo. The perfusion, diagnosticand/or transporter apparatus may be used to perfuse blood or a syntheticblood substitute through an organ while monitoring the organ and theorgan outflow to analyze the condition of the organ and/or to determinethe effect on it of the various treatments.

Preferred methods according to the present invention focus on threeconcepts in order to preserve an organ's viability prior to transplantof the organ into a donee body—treating the cellular mitochondria tomaintain and/or restore pre-ischemia energy and enzyme levels,preventing general tissue damage to the organ, and preventing thewashing away of or damage to the vascular endothelial lining of theorgan.

The mitochondria are the energy source in cells. They need large amountsof oxygen to function. When deprived of oxygen, their capacity toproduce energy is reduced or inhibited. Additionally, at temperaturesbelow 20° C. the mitochondria are unable to utilize oxygen to produceenergy. By perfusing the organ with an oxygen rich medical fluid atnormothermic temperatures, the mitochondria are provided with sufficientamounts of oxygen so that pre-ischemia levels of reserve high energynucleotide, that is, ATP levels, in the organ reduced by the lack ofoxygen are maintained and/or restored along with levels of enzymes thatprotect the organ's cells from free radical scavengers. Pyruvate richsolutions, such as that disclosed in U.S. Pat. No. 5,066,578, areincapable of maintaining and/or restoring an organ's pre-ischemia energylevels and only function in the short term to raise the level of ATP asmall amount. That is, organs naturally have significant pyruvatelevels. Providing an organ with additional pyruvate will not assist inrestoring and/or maintaining the organ's pre-ischemia energy levels ifthe mitochondria are not provided with sufficient oxygen to produceenergy. Thus, the normothermic perfusion fluid may contain pyruvate butmay also contain little or no pyruvate. For example, it can contain lessthan 6 mM of pyruvate, 5 mM, 4 mM, or even no pyruvate. Other knownpreservation solutions, such as that disclosed in U.S. Pat. No.5,599,659, also fail to contain sufficient oxygen to restore and/ormaintain pre-ischemia energy and enzyme levels.

After maintaining and/or restoring the organ's pre-ischemia energylevels by perfusing the organ with an oxygen rich first medical fluid atnormothermic or near-normothermic temperatures (the normothermic mode),the organ is perfused with a second medical fluid at hypothermictemperatures (the hypothermic mode). The hypothermic temperatures slowthe organ's metabolism and conserve energy during storage and/ortransport of the organ prior to introduction of the organ into a doneebody. The medical fluid utilized in the hypothermic mode contains littleor no oxygen, which cannot be utilized by mitochondria to produce energybelow approximately 20° C. The medical fluid may include antioxidantsand other tissue protecting agents, such as, for example, ascorbic acid,glutathione, water soluble vitamin E, catalase, or superoxide dismutaseto protect against high free radical formation which occurs at lowtemperatures due to the reduction in catalase/superoxide dismutaseproduction. Further, various drugs and agents such as hormones,vitamins, nutrients, antibiotics and others may be added to eithersolution where appropriate. Additionally, vasodilators, such as, forexample, peptides, may be added to the medical fluid to maintain floweven in condition of injury.

Prior to any normothermic perfusion with the oxygen rich first medicalfluid at normothermic temperatures, the organ may be flushed with amedical solution containing little or no oxygen and preferablycontaining antioxidants. The flushing is usually performed athypothermic temperatures but can, if desired and/or as necessary, beperformed at normothermic or near-normothermic temperatures. Flushingcan be followed by one or more of hypothermic perfusion, normothermicperfusion, and/or static storage, in any necessary and/or desired order.In some cases, normothermic perfusion may not be necessary.

The normothermic perfusion, with or without prior hypothermic flushing,may also be performed on an organ that has already been subjected tohypothermic temperatures under static or perfusion conditions, as wellas on normothermic organs.

The organ may be perfused at normothermic or near-normothermictemperatures to sustain, monitor and/or restore its viability priorand/or subsequent to being perfused at hypothermic temperatures forstorage and then may be transported without or preferably withhypothermic perfusion. Also, the normothermic perfusion may be performedin vivo prior to removal of the organ from the donor body. Further, theorgan may be perfused at normothermic temperatures to sustain, monitorand/or restore its viability prior to being perfused at hypothermictemperatures preparatory to storage and/or transport. Then the organ maybe transplanted into a donee body while remaining at hypothermictemperatures, or it may first be subjected to normothermic perfusion tohelp it recover from the effects of storage and/or transport. In thelatter case, it may then be transplanted at normothermic temperatures,or preferably, be hypothermically perfused again for transplantation athypothermic temperatures. After transplant, the organ may optionallyagain be perfused at normothermic temperatures in vivo, or allowed towarm up from the circulation of the donee.

By way of Example only, and without being limited thereto, FIG. 16 showsan exemplary diagram of possible processing steps according to theinvention. The Figure shows various possible processing steps ofmultiple organ recovery (MOR) from organ explant from the organ donorthrough implant in the donee, including possible WIT (warm ischemiatime) and hypoxia damage assessment. Several exemplary scenarios are setforth in the following discussion.

For example, in one embodiment of the present invention, the organ canbe harvested from the donor under beating heart conditions. Followingharvesting, the organ can be flushed, such as with any suitable solutionor material including, but not limited to VIASPAN (a preservationsolution available from DuPont), other crystalloid solution, dextran,HES (hydroxyethyl starch), solutions described in U.S. patentapplication Ser. No. 09/628,311, filed Jul. 28, 2000, now U.S. Pat. No.6,492,103, the entire disclosure of which is hereby incorporated byreference, or the like. The organ can then be stored statically, forexample, at ice temperatures (for example of from about 1 to about 10°C.).

In another embodiment, such as where the organ has minimal WIT andminimal vascular occlusion, a different procedure can be used. Here, theorgan can again be harvested under beating heart conditions, followed byflushing, preferably at hypothermic temperatures. If necessary totransport the organ, the organ can be stored in a suitable transporterat, for example, ice temperatures. Flow to the organ can be controlledby a set pressure maximum, where preset pressure minimum and pressuremaximum values control the pulse wave configuration. If necessary tostore the organ for a longer period of time, such as for greater than 24hours, the organ can be placed in the MOR. In the MOR, a suitableperfusate can be used, such as a crystalloid solution, dextran or thelike, and preferably at hypothermic temperatures. Preferably, thehypothermic temperatures are from about 4 to about 10° C., but higher orlower temperatures can be used, as desired and/or necessary. Preferably,the perfusate solution contains specific markers to allow for damageassessment, although damage assessment can also be made by other knownprocedures. When desired, the organ can then be returned to thetransporter for transport to the implant site.

As a variation of the above procedure, an organ having minimal WIT andminimal vascular occlusion can be harvested under non-beating heartconditions. Here, the organ can flushed, preferably at hypothermictemperatures and, if necessary, stored for transport in a suitabletransporter at, for example, ice temperatures. As above, flow to theorgan can be controlled by a set pressure maximum, where preset pressureminimum and pressure maximum values control the pulse waveconfiguration. The organ can be placed in the MOR, either for extendedstorage and/or for damage assessment. In the MOR, a suitable perfusatecan be used, such as a crystalloid solution, dextran or the like, andpreferably at hypothermic temperatures. Preferably, the hypothermictemperatures are from about 4 to about 10° C., but higher or lowertemperatures can be used, as desired and/or necessary. Preferably, theperfusate solution contains specific markers to allow for damageassessment, although damage assessment can also be made by other knownprocedures. Following hypothermic perfusion, a second perfusion can beutilized, preferably at normothermic temperatures. Any suitableperfusion solution can be used for this process, including solutionsthat contain, as desired, oxygenated media, nutrients, and/or growthfactors. Preferably, the normothermic temperatures are from about 12 toabout 24° C., but higher or lower temperatures can be used, as desiredand/or necessary. The normothermic perfusion can be conducted for anysuitable period of time, for example, for from about 1 hour to about 24hours. Following recovery from the normothermic perfusion, the organ ispreferably returned to a hypothermic profusion using, for example, asuitable solution such as a crystalloid solution, dextran or the like,and preferably at hypothermic temperatures. When desired, the organ canthen be returned to the transporter for transport to the implant site.

In embodiments where the organ has high WIT, and/or where there is ahigh likelihood of or actual; vascular occlusion, variations on theabove processes can be used. For example, in the case where the organ isharvested under non-beating heart conditions, the organ can be flushedas described above. In addition, however, free radical scavengers can beadded to the flush solution, if desired. As above, the organ can bestored for transport in a suitable transporter at, for example, icetemperatures, where flow to the organ can be controlled by a setpressure maximum, and where preset pressure minimum and pressure maximumvalues control the pulse wave configuration. The organ can be placed inthe MOR, either for extended storage and/or for damage assessment. Inthe MOR, a suitable perfusate can be used, such as a crystalloidsolution, dextran or the like, and preferably at hypothermictemperatures. Preferably, the hypothermic temperatures are from about 4to about 10° C., but higher or lower temperatures can be used, asdesired and/or necessary. Preferably, the perfusate solution containsspecific markers to allow for damage assessment, although damageassessment can also be made by other known procedures. Followinghypothermic perfusion, a second perfusion can be utilized, preferably atnormothermic temperatures. Any suitable perfusion solution can be usedfor this process, including solutions that contain, as desired,oxygenated media, nutrients, and/or growth factors. Preferably, thenormothermic temperatures are from about 12 to about 24° C., but higheror lower temperatures can be used, as desired and/or necessary. Thenormothermic perfusion can be conducted for any suitable period of time,for example, for from about 1 hour to about 24 hours. If desired, andparticularly in the event that vascular occlusion is determined orassumed to be present, a further perfusion can be conducted at highernormothermic temperatures, for example of from about 24 to about 37° C.This further perfusion can be conducted using a suitable solution thatcontains a desired material to retard the vascular occlusion. Suchmaterials include, for example, clotbusters such as streptokinase.Following recovery from the normothermic perfusion(s), the organ ispreferably returned to a hypothermic profusion using, for example, asuitable solution such as a crystalloid solution, dextran or the like,and preferably at hypothermic temperatures. When desired, the organ canthen be returned to the transporter for transport to the implant site.

The organ cassette according to the present invention allows an organ(s)to be easily transported to an organ recipient and/or between organperfusion, diagnostic and/or portable transporter apparatus, such as,for example, transporter 1900 described above or a conventional cooleror a portable container such as that disclosed in co-pending U.S.application Ser. No. 09/161,919, now U.S. Pat. No. 6,209,343. Becausethe organ cassette may be provided with openings to allow the insertionof tubing of an organ perfusion, transporter or diagnostic apparatusinto the cassette for connection to an organ disposed therein, or may beprovided with its own tubing and connection device or devices to allowconnection to tubing from an organ perfusion, transporter or diagnosticapparatus and/or also with its own valve, it provides a protectiveenvironment for an organ for storage, analysis and/or transport whilefacilitating insertion of the organ into and/or connection of an organto the tubing of an organ perfusion, transporter or diagnostic device.Further, the organ cassette may also include a handle to facilitatetransport of the cassette and may be formed of a transparent material sothe organ may be visually monitored.

Optionally, transporter 1900 and/or cassette 65 may include a GlobalPositioning System (GPS) (not shown) to allow tracking of the locationof the organ(s). The apparatus may also include a data logger and/ortransmitter (not shown) to allow monitoring of the organ(s) at thelocation of the apparatus or at another location.

The method of the invention will be discussed below in terms of theoperation of the apparatus shown in FIG. 2. However, other apparatus maybe used to perform the inventive method.

As previously discussed, the apparatus discussed above can operate intwo modes: a normothermic perfusion mode and a hypothermic perfusionmode. The normothermic perfusion mode will be discussed first followedby a discussion of hypothermic perfusion mode. Repetitive descriptionwill be omitted as much as possible.

In the normothermic or near-normothermic perfusion mode, an organ isperfused for preferably ½ to 6 hours, more preferably ½ to 4 hours, mostpreferably ½ to 1 hour, with a medical fluid maintained preferablywithin a range of approximately 10° C. to 38° C., more preferably 12° C.to 35° C., most preferably 12° C. to 24° C. or 18° C. to 24° C. (forexample, room temperature 22-23° C.) by the thermoelectric unit 30 adisposed in heat exchange communication with the medical fluid reservoir10.

As discussed above, in this mode, the medical fluid is preferably anoxygenated cross-linked hemoglobin-based bicarbonate solution.Cross-linked hemoglobin-based medical fluids can deliver up to 150 timesmore oxygen to an organ per perfusate volume than, for example, a simpleUniversity of Wisconsin (UW) gluconate type perfusate. This allowsnormothermic perfusion for one to two hours to partially or totallyrestore depleted ATP levels. However, the invention is not limited tothis preservation solution. Other preservation solutions, such as thosedisclosed in U.S. Pat. Nos. 5,149,321, 5,234,405 and 5,395,314 andco-pending U.S. patent application Ser. No. 08/484,601, now U.S. Pat.No. 5,827,222, and U.S. patent application Ser. No. 09/628,311, now U.S.Pat. No. 6,492,103, the entire disclosures of which are herebyincorporated by reference, may also be appropriate.

In the normothermic perfusion mode, the medical fluid is fed directly toan organ disposed within the organ chamber 40 from one or the other ofbags 15 a, 15 b via tubing 50 a,50 b,50 c or 50 d,50 e,50 c,respectively. The organ is perfused at flow rates preferably within arange of approximately 3 to 5 ml/gram/min. Pressure sensor P1 relays theperfusion pressure to the microprocessor 150, which varies the pressuresupplied by the pressure source 20 to control the perfusion pressureand/or displays the pressure on the control and display areas 5 a formanual adjustment. The pressure is preferably controlled within a rangeof approximately 10 to 100 mm Hg, preferably 50 to 90 mm Hg, by thecombination of the pressure source 20 and pressure cuff 15 a, 15 b inuse and the stepping motor/cam valve 65. The compressor and cuffsprovide gross pressure control. The stepping motor/cam valve 65 (orother variable valve or pressure regulator), which is also controlled bythe operator, or by the microprocessor 150 in response to signals fromthe pressure sensor P1, further reduces and fine tunes the pressureand/or puts a pulse wave on the flow into the organ 60. If the perfusionpressure exceeds a predetermined limit, the stepping motor/cam valve 65may be activated to shut off fluid flow to the organ 60.

The specific pressures, flow rates and length of perfusion time at theparticular temperatures will vary depending on the particular organ ororgans being perfused. For example, hearts and kidneys are preferablyperfused at a pressure of approximately 10 to 100 mm Hg and a flow rateof approximately 3 to 5 ml/gram/min. for up to approximately 2 to 4hours at normothermic temperatures to maintain and/or restore theviability of the organ by restoring and/or maintaining pre-ischemiaenergy levels of the organ, and are then preferably perfused at apressure of approximately 10 to 30 mm Hg and a flow rate ofapproximately 1 to 2 ml/gram/min. for as long as approximately 72 hoursto 7 days at hypothermic temperatures for storage and/or transport.However, these criteria will vary depending on the condition of theparticular organ, the donor body and/or the donee body and/or on thesize of the particular organ. One of ordinary skill in the art canselect appropriate conditions without undue experimentation in view ofthe guidance set forth herein.

Effluent medical fluid collects in the bottom of the organ chamber 40and is maintained within the stated temperature range by the secondthermoelectric unit 30 b. The temperature sensor T2 relays the organtemperature to the microprocessor 150, which controls the thermoelectricunit 30 a to adjust the temperature of the medical fluid and organ bathto maintain the organ 60 at the desired temperature, and/or displays thetemperature on the control and display areas 5 c for manual adjustment.

Collected effluent medical fluid is pumped out by the pump 80 via tubing81 through the filter unit 82 and then returned to the organ bath. Thisfilters out surgical and/or cellular debris from the effluent medicalfluid and then returns filtered medical fluid to act as the bath for theorgan 60. Once the level sensor L2 senses that a predetermined level ofeffluent medical fluid is present in the organ chamber 40 (preferablyenough to maintain the organ 60 immersed in effluent medical fluid),additional effluent medical fluid is pumped out by the pump 90 throughtubing 91. The temperature sensor T1 relays the temperature of the organbath to the microprocessor 150, which controls the thermoelectric unit30 b to adjust the temperature of the medical fluid to maintain theorgan 60 at the desired temperature and/or displays the temperature onthe control and display area 5 c for manual adjustment and monitoring.

As noted above, the medical fluid can be directed to waste in a singlepass mode or recirculated eventually back to the organ and/or bath(recirculation mode.)

Along tubing 91, the recirculated medical fluid is first pumped throughthe filter unit 95. Use of a cross-linked hemoglobin medical fluidallows the use of sub-micron filtration to remove large surgical debrisand cellular debris, as well as bacteria. This allows the use of minimalantibiotic levels, aiding in preventing organ damage such as renaldamage.

Next, the recirculated medical fluid is pumped through the CO,scrubber/O₂ membrane 100. The medical fluid passes over the hydrophobicmacroporous membrane with a hydrophilic coating (for example, Hypol) anda low vacuum is applied on the opposite side by activating valve VV₁which removes CO, from the recirculated medical fluid.

Subsequently, a portion of the medical fluid then enters the oxygenator110 (for example, a JOSTRA™ oxygenator) and a portion is divertedtherearound passing via tubing 111 though the pH, pO₂, pCO₂, LDH, T/GSTand Tprotein sensor V1. At this point two gases, preferably 100% oxygenand 95/5% oxygen/carbon dioxide, are respectively placed on the oppositesides of the membrane depending on the pH level of the diverted medicalfluid. The gases are applied at a pressure of up to 200 mm Hg,preferably 50 to 100 mm Hg, preferably through a micrometer gas valveGV₃. The cross-linked hemoglobin-based bicarbonate medical fluid may beformulated to require a pCO₂ of approximately 40 mm Hg to be at the midpoint (7.35) of a preferred pH range of 7.25-7.45.

If the medical fluid exiting the oxygenator is within the preferred pHrange (e.g., 7.25-7.45), 100% oxygen is delivered to the gas exchangechamber, and valve LV₁ is then not opened, allowing the perfusate toreturn to the reservoir 10 into the bag 15 a or 15 b not in use. If thereturning perfusate pH is outside the range on the acidic side (e.g.,less than 7.25), 100% oxygen is delivered to the gas exchange chamberand valve LV₁ is then opened allowing the perfusate to return to theorgan chamber 40. Actuation of syringe pump 131 pumps, for example, onecc of a bicarbonate solution from the bicarbonate reservoir 130, viatubing 132 into the organ bath. Medical fluids with high hemoglobincontent provide significant buffering capacity. The addition ofbicarbonate aids in buffering capacity and providing a reversible pHcontrol mechanism.

Tithe returning perfusate pH is outside the range on the basic side(e.g., greater than 7.25), 95/5% oxygen/carbon dioxide is delivered tothe gas exchange chamber and valve LV₁ is not actuated, allowing theperfusate to return to the bag 15 a or 15 b not in use. The bag 15 a or15 b not in use is allowed to degas (e.g., any excess oxygen) throughvalve GV₄. When the bag 15 a or 15 b in use has approximately 250 ml orless of medical fluid remaining therein, its respective cuff 16 a, 16 bis allowed to vent via its respective gas valve GV₁, GV₂. Then, therespective cuff 16 a, 16 b of the bag 15 a or 15 b previously not in useis supplied with gas from the compressed gas source 20 to delivermedical fluid to the organ to continue perfusion of the organ.

In the hypothermic mode, an organ is perfused with a cooled medicalfluid, preferably at a temperature within a range of approximately 1° C.to 15° C., more preferably 4° C. to 10° C., most preferably around 10°C. The medical fluid is preferably a crystalloid perfusate withoutoxygenation and preferably supplemented with antioxidants and othertissue protecting agents, such as, for example, ascorbic acid,glutathione, water soluble vitamin E, catalase, or superoxide dismutase.

Instead of feeding the medical fluid directly to the organ, the medicalfluid may be fed from the reservoir tank 17 via tubing 51 into anintermediary tank 70 preferably having a pressure head of approximately5 to 40 mm Hg, more preferably 10 to 30 mm Hg, most preferably around 20mm Hg. Medical fluid is then fed by gravity or, preferably, pressure,from the intermediary tank 70 to the organ 60 along tubing 50 c byactivating a valve LV₆. The level sensor 71 in the intermediary tank 70is used to control the feed from reservoir tank 17 to maintain thedesired pressure head. Because the medical fluid is fed to the organ bygravity or, preferably, pressure, in the hypothermic mode, there is lessperfusion pressure induced damage to the delicate microvasculature ofthe organ. In fact, the pressure at which the organ is perfused islimited by the pressure head to at most 40 mm Hg.

The stepping motor/cam valve 205 (or other variable valve or pressureregulator) may be arranged on the tubing 50 c to provide pulsatiledelivery of the medical fluid to the organ 60, to decrease the pressureof the medical fluid fed into the organ 60 for control purposes, or tostop flow of medical fluid into the organ 60, as described above.

Further, in the hypothermic mode, because the organ 60 has less of ademand for nutrients, the medical fluid may be provided to the organ 60intermittently (e.g., every two hours at a flow rate of up toapproximately 100 ml/min.), or at a slow continuous flow rate (e.g., upto approximately 100 ml/min.) over a long period of time. Intermittentperfusion can be implemented in the single pass mode or recirculationmode. The pump 80, filter unit 82 and tube 81 may be used to filter theorgan bath along with use of the pH, pO₂, pCO₂, LDH, T/GST and Tproteinsensor; however, because the organ is unable to utilize oxygen athypothermic temperatures, the oxygenator is not used. If desired and/ornecessary, adequate oxygen can be obtained from filtered room air orother suitable source.

Both the perfusate flow and the temperature regulation can beautomatically controlled. Such automatic control allows a rapid andreliable response to perfusion conditions during operation. Automaticflow control can be based on the parameters measured from the system,including the perfusate flow rate, the perfusate pH exiting the organ,the organ inlet pressure or timed sequences such as pre-selected flowrates or switching between perfusate modes. Preferably, the flow controlis based on pressure monitoring of the perfusate inflow into the organ.The benefits of automatic flow control include maintaining properoxygenation and pH control while operating under continuous flow orcontrolled intermittent flow. Thermal control of the thermoelectricdevices (TED) can regulate the temperature of the organ cassette orcontainer and the perfusate reservoir. The thermal control is based onthermal measurements made for example by thermistor probes in theperfusate solution or inside the organ or by sensors in the TED.

The automatic control is preferably effected by an interactive controlprogram using easily operated menu icons and displays. The parametersmay be prestored for selection by a user or programmed by the userduring operation of the system. The control program is preferablyimplemented on a programmed general purpose computer. However, thecontroller can also be implemented on a special purpose computer, aprogrammed microprocessor or microcontroller and peripheral integratedcircuit elements, an ASIC or other integrated circuit, a digital signalprocessor, a hardwired electronic or logic circuit such as a discreteelement circuit, a programmable logic device such as a PLD, PLA, FPGA orPAL, or the like. In general, any device capable of implementing afinite state machine that is in turn capable of implementing the controlprocess described herein may be used. The control program is preferablyimplemented using a ROM. However, it may also be implemented using aPROM, an EPROM, an EEPROM, an optical ROM disk, such as a CD-ROM orDVD-ROM, and disk drive or the like. However, if desired, the controlprogram may be employed using static or dynamic RAM. It may also beimplemented using a floppy disk and disk drive, a writable optical diskand disk drive, a hard drive, flash memory or the like.

In operation, as seen in FIG. 15, the basic steps of operation tocontrol perfusion of one or more organs include first inputting organdata. The organ data includes at least the type of organ and the mass.Then, the program will prompt the user to select one or more types ofperfusion modes. The types of perfusion modes, discussed above, includehypothermic perfusion, normothermic perfusion, and sequential perfusionusing both normothermic and hypothermic perfusion. When bothnormothermic and hypothermic perfusion are employed, the user can selectbetween medical fluids at different temperatures. Of course, the systemincludes default values based on previously stored values appropriatefor the particular organ. The user may also select intermittentperfusion, single pass perfusion, and recirculation perfusion. Dependingon the type of perfusion selected, aerobic or anaerobic medical fluidsmay be specified.

Next, the type of flow control for each selected perfusion mode is set.The flow control selector selects flow control based on at least one ofperfusate flow rate, perfusate pH, organ inlet pressure and timedsequences. In the preferred embodiment, the flow control is based ondetected pressure at the perfusion inlet to the organ. The flow of themedical fluid is then based on the selected perfusion mode and flowcontrol.

During operation the conditions experienced by the system, in particularby the organ and the perfusate, are detected and monitored. The detectedoperating conditions are compared with prestored operating conditions. Asignal can then be generated indicative of organ viability based on thecomparison. The various detectors, sensors and monitoring devices aredescribed above, but include at least a pressure sensor, a pH detector,an oxygen sensor and a flow meter.

The control system may also include a thermal controller for controllingtemperature of at least one of the perfusate and the organ. The thermalcontroller can control the temperature of the medical fluid reservoirsand the organ container by controlling the TEDs. As noted above,temperature sensors are connected to the controller to facilitatemonitoring and control.

The control system may be manually adjusted at any time or set to followdefault settings. The system includes a logic circuit to prevent theoperator from setting parameters that would compromise the organ'sviability. As noted above, the system may also be operated in a manualmode for sequential hypothermic and/or normothermic perfusion, as wellas in the computer controlled mode for sequential hypothermic and/ornormothermic perfusion.

The above described apparatus and method may be used for child or smallorgans as well as for large or adult organs with modification as neededof the cassettes and or of the pressures and flow rates accordingly. Aspreviously discussed, the organ cassette(s) can be configured to theshapes and sizes of specific organs or organ sizes. The apparatus andmethod can also be used to provide an artificial blood supply to, such,for example, artificial placentas cell cultures, for growing/cloningorgan(s).

While the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations may be apparent to those skilled in the art. Accordingly,the preferred embodiments of the invention as set forth herein areintended to be illustrative, not limiting. Various changes may be madewithout departing from the spirit and scope of the invention.

1. An organ perfusion system for perfusing an organ comprising: a first pump fluidly connected to a first perfusion circuit with a first pressure and/or flow controller disposed downstream of the first pump; a second pump fluidly connected to a second perfusion circuit with a second pressure and/or flow controller disposed downstream of the second pump; and a controller configured to control the first pressure and/or flow controller and the second pressure and/or flow controller, wherein the first perfusion circuit is configured to connect to a first area of the organ and the second perfusion circuit is configured to connect to a second area of the organ, and the first pressure and/or flow controller and the second pressure and/or flow controller are controlled so that perfusion of the first area and the second area are different.
 2. The organ perfusion system according to claim 1, wherein the organ is a liver and the first area is a hepatic artery of the liver and the second area is a portal vein of the liver.
 3. The organ perfusion system according to claim 1, further comprising: an organ cassette for holding the organ; wherein the first perfusion circuit and the second perfusion circuit pass into and/or out of the organ cassette by way of at least one opening in the organ cassette.
 4. The organ perfusion system according to claim 1, wherein at least one of the first perfusion circuit and the second perfusion circuit provide oxygenation to a perfusate.
 5. The organ perfusion system according to claim 1, wherein the first perfusion circuit provides oxygenation to a first perfusate and the second perfusion circuit provides oxygenation to a second perfusate.
 6. The organ perfusion system according to claim 1, wherein the organ is perfused at normothermic temperature.
 7. The organ perfusion system according to claim 1, wherein the first perfusion circuit and the second perfusion circuit are independent from one another.
 8. The organ perfusion system according to claim 1, wherein the first perfusion circuit and the second perfusion circuit are configured to have different flow rates.
 9. The organ perfusion system according to claim 1, wherein the first perfusion circuit provides pulsatile flow and the second perfusion circuit provides continuous flow.
 10. The organ perfusion system according to claim 1, wherein: the first perfusion circuit further comprises a first pressure sensor and a first flow sensor, and the second perfusion circuit further comprises a second pressure sensor and a second flow sensor.
 11. The organ perfusion system according to claim 1, wherein the first perfusion circuit comprises a first branch that is configured to wash the organ, the first branch being upstream of the first pressure and/or flow controller.
 12. The organ perfusion system according to claim 11, wherein the first branch comprises a first valve.
 13. The organ perfusion system according to claim 11, wherein the second perfusion circuit comprises a second branch that is configured to wash the organ, the second branch being upstream of the second pressure and/or flow controller.
 14. The organ perfusion system according to claim 13, wherein the second branch comprises a first valve.
 15. The organ perfusion system according to claim 1, wherein the first perfusion circuit includes a first oxygenator between the first pump and the organ and the second perfusion circuit includes a second oxygenator between the second pump and the organ.
 16. The organ perfusion system according to claim 1, wherein the first pressure and/or flow controller is a flow control valve.
 17. The organ perfusion system according to claim 1, wherein the second pressure and/or flow controller is a flow control valve.
 18. A method for perfusing an organ comprising: fluidly connecting a first pump and a first perfusion circuit with a first pressure and/or flow controller downstream of the first pump to a first area of the organ; fluidly connecting a second pump and a second perfusion circuit with a second pressure and/or flow controller downstream of the second pump to a second area of the organ; perfusing the first area of the organ with the first pump and the first perfusion circuit; perfusing the second area of the organ with the second pump and the second perfusion circuit, and controlling perfusion of the first area of the organ and perfusion of the second area of the organ to be different.
 19. The method for perfusing an organ according to claim 18, further comprising: oxygenating a perfusate in at least one of the first perfusion circuit and the second perfusion circuit.
 20. The method for perfusing an organ according to claim 18, oxygenating a first perfusate in the first perfusion circuit and oxygenating a second perfusate in the second perfusion circuit.
 21. The method for perfusing an organ according to claim 18, further comprising: monitoring the first perfusion circuit with a first pressure sensor and a first flow sensor, and monitoring the second perfusion circuit with a second pressure sensor and a second flow sensor.
 22. The method for perfusing an organ according to claim 21, further comprising: controlling the perfusing the first area based on the monitoring of the first perfusion circuit, and controlling the perfusing the second area based on the monitoring of the second perfusion circuit.
 23. An organ perfusion system for perfusing an organ comprising: a first means for pumping that is fluidly connected to a first circuit means for perfusing and a first pressure and/or flow control means downstream of the first means for pumping; a second means for pumping that is fluidly connected to a second circuit means for perfusing and a second pressure and/or flow control means downstream of the second means for pumping; and a control means for controlling the first pressure and/or flow control means and the second pressure and/or flow control means, wherein the first circuit means is configured to connect to a first area of the organ and the second circuit means is configured to connect to a second area of the organ, and the first pressure and/or flow control means and the second pressure and/or flow control means are controlled so that perfusion of the first area and the second area are different. 